Biomedical subjects

C A Bondy

Publications and source records attributed to C A Bondy.

At least 37 records · Page 2Linked to original sources

PubMed1999

Androgen and follicle-stimulating hormone interactions in primate ovarian follicle development.

We have previously shown that androgens stimulate early stages of follicular development and that granulosal androgen receptor (AR) gene expression is positively correlated with follicular growth. The present study was aimed at elucidating potential interactions between FSH and androgens in follicular development. Study groups included eight normal cycling rhesus monkeys (five follicular and three luteal-phase), eight testosterone (T)-treated, and four FSH-treated animals. Examination of sequential ovary sections revealed selective colocalization of AR and FSH receptor (FSHR) messenger RNAs (mRNAs) in healthy, growing follicles. Moreover, individual follicles demonstrate a highly significant (P < 0.001) positive correlation between FSHR and AR mRNA levels in all study groups. Androgen treatment significantly increased granulosa cell FSHR mRNA abundance (by approximately 50-100%, depending on follicle size). FSH treatment increased granulosa AR mRNA levels only in primary follicles. The finding that T augments follicular FSHR expression suggests that androgens promote follicular growth and estrogen biosynthesis indirectly, by amplifying FSH effect, and may partially explain the enhanced responsiveness to gonadotropin stimulation noted in women with polycystic ovary syndrome.

Androgens↗

PubMed1998

Biochemical and morphometric analyses show that myelination in the insulin-like growth factor 1 null brain is proportionate to its neuronal composition.

To elucidate the role of insulin-like growth factor 1 (IGF1) in the normal development of brain myelination, we used behavioral, biochemical, and histological analyses to compare the myelination of brains from Igf1(-/-) and wild-type (WT) littermate mice. The studies were conducted at postnatal day 40, at which time the Igf1(-/-) mice weighed approximately 66% less than wild-type mice. However, the Igf1(-/-) brain weight was only reduced by approximately 34%. Formal neurological testing showed no sign of central or peripheral myelinopathy in Igf1(-/-) mice. Myelin composition was not significantly different, and myelin concentration, normalized to brain weight or protein, was equal in Igf1(-/-) and WT mice. Likewise, concentrations of myelin-specific proteins (MBP, myelin proteolipid protein, MAG, and 2',3'-cyclic nucleotide,3'-phosphodiesterase) were not significantly different in Igf1(-/-) and WT mice. The myelin-associated lipids galactocerebroside and sulfatide were modestly reduced in Igf1(-/-) brains. Regional oligodendrocyte populations and myelin staining patterns were comparable in Igf1(-/-) and WT brains, with the notable exception of the olfactory system. The Igf1(-/-) olfactory bulb was profoundly reduced in size and was depleted of mitral neurons and oligodendrocytes, and its efferent tracts were depleted of myelin. In summary, this study shows that myelination of the Igf1(-/-) brain is proportionate to its neuronal composition. Where projection neurons are preserved despite the deletion of IGF1, as in the cerebellar system, oligodendrocytes and myelination are indistinguishable from wild type. Where projection neurons are depleted, as in the olfactory bulb, oligodendrocytes are also depleted, and myelination is reduced in proportion to the reduced projection neuron mass. These data make a strong case for the primacy of axonal factors, not including IGF1, in determining oligodendrocyte survival and myelination.

Animals↗

PubMed1998

Androgens stimulate early stages of follicular growth in the primate ovary.

The concept that androgens are atretogenic, derived from murine ovary studies, is difficult to reconcile with the fact that hyperandrogenic women have more developing follicles than normal-cycling women. To evaluate androgen's effects on primate follicular growth and survival, normal-cycling rhesus monkeys were treated with placebo-, testosterone-(T), or dihydrotestosterone-sustained release implants, and ovaries were taken for histological analysis after 3-10 d of treatment. Growing preantral and small antral follicles up to 1 mm in diameter were significantly and progressively increased in number and thecal layer thickness in T-treated monkeys from 3-10 d. Granulosa and thecal cell proliferation, as determined by immunodetection of the Ki67 antigen, were significantly increased in these follicles. Preovulatory follicles (> 1 mm), however, were not increased in number in androgen-treated animals. Follicular atresia was not increased and there were actually significantly fewer apoptotic granulosa cells in the T-treated groups. Dihydrotestosterone treatment had identical effects, indicating that these growth-promoting actions are mediated by the androgen receptor. These findings show that, over the short term at least, androgens are not atretogenic and actually enhance follicular growth and survival in the primate. These new data provide a plausible explanation for the pathogenesis of "polycystic" ovaries in hyperandrogenism.

Androgens↗

PubMed1998

Alterations in GLUT1 and GLUT3 glucose transporter gene expression following unilateral hypoxia-ischemia in the immature rat brain.

The brain damage produced by unilateral cerebral hypoxia-ischemia in the immature rat results from major alterations in cerebral energy metabolism and glucose utilization which begin during the course of the insult and proceed into the recovery period. Consistent with a lack of pathology, the alterations in the hemisphere contralateral to the carotid artery ligation are transient and return to normal within 24 h of recovery, whereas the hemisphere ipsilateral to the ligation exhibits both early and late responses, and infarction. The facilitative glucose transporter proteins mediate glucose transport across the blood-brain barrier (55 kDa GLUT1), and into neurons and glia (GLUT3 and 45 kDa GLUT1), and demonstrate both early and late responses to perinatal hypoxia-ischemia. This study employed in situ hybridization histochemistry to investigate the temporal and regional patterns of GLUT1 and GLUT3 gene expression following a severe (2.5 h) hypoxic-ischemic insult in the 7-day old rat brain. Enhanced GLUT1 mRNA expression was apparent in cerebral microvessels of both hemispheres and remained elevated in the ipsilateral hemisphere through 24 h of recovery, consistent with our previous observation of increased microvascular 55 kDa GLUT1 protein. The expression of the neuronal isoform, GLUT3, was enhanced in penumbral regions, such as piriform cortex and amygdala, but was rapidly reduced in the affected areas of cortex, hippocampus and thalamus, reflecting necrosis. The late response, observed at 72 h of recovery, was characterized by extensive necrosis in the ipsilateral hemisphere, loss of GLUT3 expression, and a gliotic reaction including increased GLUT1 in GFAP-positive astrocytes. This study demonstrates that cerebral hypoxia-ischemia in the immature rat produces both immediate-early and long-term effects on the glucose transporter proteins at the level of gene expression.

Animals↗

PubMed1998

The genetic origins of ovarian failure.

Premature ovarian failure (POF) is a condition characterized by cessation of ovarian function before the age of 40. The recent meeting at the National Institute of Child Health and Human Development brought together experts from diverse disciplines to share current perspectives on the genetic and physiologic origins of POF, with the idea that insights gained from these studies may provide important clues about the regulation of normal ovarian aging and perhaps aging processes in general. It was suggested that several murine genes, including Zfx, c = kit, and the kit ligand, should be fertile candidates for investigation of the etiology of POF in human families. The specific roles of the human DIA and FMR1 gene products in germ cell development need clarification in murine models, and there are more as yet unidentified genes residing on the long arm of the X chromosome that are also implicated in the regulation of human ovarian function. Genes acting at later stages of oocyte or ovarian follicle function, such as gonadotropin hormones and receptors, are responsible for POF in some women. POF has been found to be a heterogeneous disorder, the dissection of which offers promising insights into mechanisms governing germ cell origination, migration, and proliferation, meiotic mechanisms, and factors governing oocyte maturation and survival.

Adult↗

PubMed1998

Fibroblast growth factors 1 and 2 in the primate uterus.

Fibroblast growth factors (FGF) 1 and 2 are paracrine effectors of proliferation and angiogenesis in many tissues. To elucidate potential roles for these growth factors in uterine plasticity, we used in situ hybridization histochemistry to identify the cellular sources of FGF-1 and -2 production, and immunohistochemistry to identify the cellular and extracellular deposition sites of the peptides in the primate uterus. To evaluate the effects of estradiol on uterine FGFs, uteri from ovariectomized rhesus monkeys treated with estradiol- or vehicle-containing pellets were investigated. FGF-1 and -2 mRNAs were both expressed in uterine epithelial and myometrial cells. Quantitative comparison of their mRNA levels using computerized grain counting showed no significant difference between estradiol- and vehicle-treated animals. FGF-1 immunoreactivity was detected in scattered epithelial, vascular, and myometrial cells in the vehicle-treated animals but found to be significantly more intense and widespread in estradiol-treated animals. In both conditions, FGF-1 immunostaining was predominantly nuclear. FGF-2 immunoreactivity was concentrated extracellularly in the basal lamina of both glandular and surface epithelium and was abundant and diffusely distributed within myometrial and vascular cells in both cytoplasm and nucleus. There was no apparent difference in the pattern or intensity of FGF-2 immunostaining related to estradiol treatment. These data demonstrate that major uterine cell types synthesize both FGF-1 and -2, and that the two peptides are differentially localized in uterine cellular and extracellular compartments and differentially sensitive to regulation by estradiol.

Animals↗

PubMed1998

Androgen receptor gene expression in the primate ovary: cellular localization, regulation, and functional correlations.

Excess androgens are associated with a characteristic polyfollicular ovarian morphology; however, it is not known to what extent this problem is due to direct androgen action on follicular development vs. interference with gonadotropin release at the level of the pituitary or hypothalamus. To elucidate potential androgen effects on the ovary, we investigated the cellular localization of androgen receptor (AR) messenger ribonucleic acid (mRNA) in rhesus monkey using in situ hybridization. To investigate the regulation of ovarian AR gene expression, we compared the relative abundance of AR transcripts in monkeys during follicular and luteal phases of the menstrual cycle and in monkeys treated with testosterone. To assess potential functional consequences of AR expression in the primate ovary, we compared AR mRNA levels with indexes of follicular cell proliferation and apoptosis in serial sections from individual follicles. AR mRNA expression was most abundant in granulosa cells of healthy preantral and antral follicles in the primate ovary. Theca interna and stromal cells also expressed AR mRNA, but to a lesser degree than granulosa cells. No significant cycle stage effects were noted in AR mRNA levels; however, larger numbers of animals would be necessary to definitively establish a cycle stage effect. AR mRNA level was significantly increased in granulosa cells and was decreased in theca interna and stromal cells of testosterone-treated monkeys. Importantly, granulosa cell AR mRNA abundance was positively correlated with expression of the proliferation-specific antigen Ki-67 (r = 0.91; P < 0.001) and negatively correlated with granulosa cell apoptosis (r = -0.64; P < 0.001). In summary, these data show that primate ovary AR gene expression is most abundant in granulosa cells of healthy growing follicles, where its expression is up-regulated by testosterone. The positive correlation between granulosa AR gene expression and cell proliferation and negative correlation with programmed cell death suggests that androgens stimulate early primate follicle development.

Animals↗

PubMed1997

Growth hormone treatment induces mammary gland hyperplasia in aging primates.

The decline of growth hormone (GH) and insulin-like growth factor I (IGF-I) production during aging has been likened to the decrease in gonadal steroids in menopause. The repletion of GH/IGF-I levels in aging individuals is suggested to restore the lean tissue anabolism characteristic of youth. In addition to anabolic effects on musculo-skeletal tissues, GH also stimulates mammary glandular growth in some species, although its effects on primate mammary growth remain unclear. Some clinical observations implicate GH in human mammary growth, for example, gynecomastia occurs in some children treated with GH (ref. 6), and tall stature and acromegaly are associated with an increased incidence of breast cancer. To investigate the effects of GH/IGF-I augmentation on mammary tissue in a model relevant to aging humans, we treated aged female rhesus monkeys with GH, IGF-I, GH + IGF-I or saline diluent for 7 weeks. IGF-I treatment was associated with a twofold increase, GH with a three- to fourfold increase, and GH + IGF-I with a four'-to fivefold increase in mammary glandular size and epithelial proliferation index. These mitogenic effects were directly correlated with circulating GH and IGF-I levels, suggesting that either GH or its downstream effector IGF-I stimulates primate mammary epithelial proliferation.

Aging↗

PubMed1997

Changes in facilitative glucose transporter messenger ribonucleic acid levels in the diabetic rat kidney.

Facilitative glucose transporter (GLUTs 1, 2, 4, and 5) messenger RNAs (mRNAs) are differentially distributed in the rat nephron: GLUT1 is widely expressed, GLUT4 is selectively concentrated in thick ascending limbs, and GLUT2 and 5 are exclusively localized in proximal tubules, consistent with differential roles for these transporters in renal glucose handling. In the present study, quantitative in situ hybridization was used to evaluate changes in these mRNA levels during acute (2 and 7 days) and chronic (30, 90, and 180 days) streptozotocin-induced diabetes mellitus (STZ-DM). Medullary GLUT1 and GLUT4 mRNA levels were significantly increased during the acute phase but returned to normal after 1 week. Cortical GLUT1 mRNA levels, however, were decreased significantly from 7 days through 6 months of STZ-DM. Cortical GLUT2 mRNA was slightly increased acutely and increased 5-fold in chronic STZ-DM, with the largest increase focally concentrated in the convoluted portion of the proximal tubule. Proximal tubule GLUT5 mRNA levels also were increased significantly during chronic STZ-DM. In summary, medullary GLUT1 and GLUT4 mRNA levels are acutely increased in STZ-DM, paralleling the increased renal epithelial metabolic activity accompanying early diabetes. Proximal tubular GLUT2 and 5 mRNA levels were increased in chronic STZ-DM, possibly adapting to the increased need for glucose transport out of these epithelial cells, whereas the concomitant decrease in cortical GLUT1 expression may reflect the decreased requirement for basolateral import of glucose into these same cells. Thus, renal GLUTs demonstrate complex, nephron segment-specific and duration-dependent responses to the effects of STZ-DM.

Acute Disease↗

PubMed1997

The mouse intraovarian insulin-like growth factor I system: departures from the rat paradigm.

Although the rat intraovarian insulin-like growth factor I (IGF-I) system is well documented, the increasing availability of null mouse mutants for components of the IGF system necessitates characterization of the mouse model as well. Therefore, we undertook to define the components of the mouse intraovarian IGF-I system and to examine its operational characteristics. The cellular pattern of ovarian gene expression was comparable in the immature rat and mouse for IGF-I and the type I IGF receptor. In both species, IGF-I messenger RNA (mRNA) is selectively expressed by granulosa cells in growing, healthy appearing follicles. Type I IGF receptor mRNA was also concentrated in granulosa cells, but was uniformly expressed in all follicles large and small, healthy and atretic appearing alike. Cellular patterns of IGF-binding protein (IGFBP) gene expression were similar in mouse and rat, except in the case of IGFBP-2. IGFBP-2 mRNA was localized to the mouse granulosa cell, in contrast to its concentration in the rat thecal-interstitial compartment. This difference in IGFBP expression pattern was also noted in cultured mouse and rat granulosa cells. Although immunoreactive IGFBP-4 (24 and 28 kDa) and IGFBP-5 (29 kDa) were shared by both species, the cultured mouse granulosa cell also featured immunoreactive IGFBP-2 (30 kDa). The mouse paradigm further differed from its rat counterpart in that a maximal dose of FSH, previously shown to suppress the elaboration of rat granulosa cell-derived IGFBPs, was without effect. The addition of IGF-I proved stimulatory to the accumulation of the 28- to 29-kDa IGFBPs, as previously reported for the rat. However, IGF-I proved inhibitory to the accumulation of the 24-kDa IGFBP (presumptive nonglycosylated IGFBP-4); no consistent effect was reported for the rat model. Functional comparisons of mouse and rat ovarian cell cultures revealed qualitatively comparable FSH-stimulated steroidogenesis, disposition of radiolabeled pregnenolone, IGF-I-amplified FSH action, and IGFBP-mediated antigonadotropic activity. These findings indicate that the mouse intrafollicular IGF-I system differs from the rat paradigm in both the makeup and regulation of granulosa cell-derived IGFBPs as well as in the intensity and character of the steroidogenic process. Studies employing the mouse model must take into account these important distinctions relative to the more established rat paradigm.

Animals↗

PubMed1997

Steroidogenic factor 1 messenger ribonucleic acid expression in steroidogenic and nonsteroidogenic human tissues: Northern blot and in situ hybridization studies.

Steroidogenic factor-1 (SF-1), a tissue-specific orphan nuclear receptor, regulates the genes of several steroidogenic enzymes, Mullerian inhibiting substance, and the gonadotrophins. Also, this transcription factor is crucial for hypothalamic, adrenal, and gonadal organogenesis in the mouse. We recently cloned the human SF-1 (hSF-1) complementary DNA (cDNA) and now report the distribution of this factor's messenger RNA (mRNA) in human tissues. Northern blot analyses of peripheral tissues revealed high hSF-1 mRNA expression in the adrenal cortex and the gonads, but no hSF-1 mRNA was detected in the placenta. High hSF-1 mRNA expression also was seen in the spleen. In this tissue, in addition to the main transcript of 3.5-4 kb seen in the adrenal and gonads, two additional transcripts of 4.4 kb and 8 kb were noted. The additional 4.4-kb transcript also was seen in several peripheral tissues and various components of the brain. However, adult liver and heart showed only the 4.4-kb transcript. In the human brain, hSF-1 mRNA expression was widespread, including several components of the limbic system. In situ hybridization studies confirmed the strong expression of hSF-1 mRNA in adrenal cortex, ovary, testis, and the spleen, primarily within reticuloendothelial cells. Thus, in the human, the hSF1 mRNA is present in both steroidogenic and nonsteroidogenic tissues, albeit not in the placenta. In the central nervous system, the expression of hSF-1 mRNA is widespread. It is composed of several different mRNA species distributed in a tissue-specific fashion. These findings suggest that hSF-1 may play a role in reticuloendothelial/immune cell maturation and/or function, as well as nervous system development and/or neurosteroid biosynthesis.

Adult↗

PubMed1996

Differential cellular pattern of gene expression for two distinct cGMP-inhibited cyclic nucleotide phosphodiesterases in developing and mature rat brain.

Cyclic GMP-inhibited phosphodiesterases are characterized by sensitivity of cAMP hydrolysis to inhibition by cGMP. This phosphodiesterase family contains at least two different isoforms (PDE3A and PDE3B) encoded by distinct genes and serving tissue-specific roles in regulation of lipolysis, glycogenolysis, myocardial contractility, and smooth muscle relaxation. Our previous work indicated an abundance of these two phosphodiesterase messenger RNAs in the embryonic rat brain, and therefore, to elucidate the potential functions of these enzymes in brain development as well as in mature brain function, the present study mapped cellular patterns of gene expression for these two enzymes from embryonic day 15 to adulthood using in situ hybridization histochemistry. Phosphodiesterase 3B isoform messenger RNA is uniformly expressed in germinal neuroepithelium and mature neurons, with distribution generally reflecting cell density. Phosphodiesterase isoform 3A messenger RNA, in contrast, demonstrates striking spatiotemporal specificity of expression, with three distinct patterns being evident. Firstly, this mRNA is highly abundant in both primary and secondary neuroepithelial germinal zones. Secondly, during early postnatal development PDE3A mRNA is transiently but highly expressed in neurons localized in basal forebrain, deep cerebellar, pontine, interpeduncular and a variety of thalamic, midbrain and brainstem nuclei. Thirdly, PDE3A mRNA is focally expressed in isolated large striatal and hippocampal neurons from the perinatal period without attenuation into adulthood. In summary, two cGMP-inhibited phosphodiesterase isoforms show distinctive patterns of gene expression in brain: PDE3B gene expression is uniform without evidence of system specificity or developmental stage specificity, suggesting that this isoform has a constitutive role in neuroepithelial metabolism, while PDE3B gene expression demonstrates a high level of spatiotemporal heterogeneity, suggesting that this isoform subserves a variety of developmental stage-specific and system-specific functions.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1996

Lobular distribution of human liver phenol and bilirubin uridine 5'-diphosphate glucuronosyltransferase messenger RNAs.

BACKGROUND & AIMS: Heterogeneity in uridine 5'-diphosphate (UDP) glucuronosyltransferase expression across the human hepatic acinus may be important in the manifestation of certain zone-specific chemical hepatotoxicities. Previous immunohistochemical studies suggested that a phenol transferase induced by polycyclic aromatic hydrocarbons may be differentially expressed in centrilobular hepatocytes of rats. The aim of this study was to assess the distribution of the phenol and bilirubin transferases in human liver at the RNA level. METHODS: In situ RNA hybridization was used with two human liver samples and specific probes for the phenol transferase RNA, HLUG P1, and the bilirubin transferase RNAs, HUG-Br1 and HUG-Br2. RESULTS: The highest density signals were observed for the bilirubin transferase RNAs, both appearing to be evenly expressed in hepatocytes across the liver lobule. Slightly higher density of HUG-Br1 message was observed in some centrilobular hepatocytes surrounding larger central vein structures. HLUG P1 RNA was expressed at low levels (approximately fivefold greater than background signal) and was evenly distributed. CONCLUSIONS: The data suggest that a species difference exists in the distribution of the human and rat phenol transferase. No evidence was found for significant zonation in the pattern of expression of either the phenol or bilirubin transferase genes in human liver.

Base Sequence↗

PubMed1996

Selective expression of insulin-like growth factor system components during porcine ovary follicular selection.

In situ hybridization was used to map anatomical patterns of insulin-like growth factor (IGF) system gene expression in the gilt ovary through the estrous cycle. IGF-I, IGF-II< and IGF-I receptor messenger RNAs (mRNAs) were coexpressed in granulosa cells of developing and dominant follicles through the follicular phase. IGF-I and IGF-I receptor mRNAs were selectively concentrated in healthy follicles, whereas IGF-II mRNA was found in all follicles regardless of incipient or overt atresia. IGF-binding protein-1 (IGFBP-1) was not detected in the gilt ovary at any stage. IGFBP-2 mRNA was most abundant in granulosa cells of small follicles and in the ovarian vasculature regardless of cycle stage. IGFBP-2 mRNA persisted in granulosa cells of preovulatory follicles and corpora lutea. IGFBP-3 mRNA was not detected in developing follicles, but was detected in all luteal phase corpora lutea, apparently expressed by theca lutein cells. IGFBP-4 demonstrated a highly dynamic pattern of gene expression, closely tracking LH receptor gene expression throughout the follicular and luteal phases of the estrous cycle. IGFBP-4 mRNA was concentrated in the theca of medium to large growing follicles, but was not detected in granulosa cells until the emergence of dominant follicles in the late follicular stage, when the granulosa cells showed morphological evidence of luteinization as well as LH receptor gene expression. IGFBP-4 mRNA expression continued in granulosa cells of corpora lutea during the luteal phase and was not detected in atretic follicles. IGFBP-5 mRNA was concentrated in the surface or germinal epithelium and in capillary endothelium, particularly in capillaries of corpora lutea. In summary, there is selective expression of IGF-I, IGF-I receptor, and IGFBP-2 and -4 mRNAs during the process of follicular selection in the gilt ovary, with IGFBP-4 expression being closely associated with follicular selection and luteinization. These observations support an important role for autocrine/paracrine IGF action modulated by IGFBP-2 and -4 in both follicular growth and differentiation in the porcine ovary.

Animals↗

PubMed1996

Sex steroid regulation of insulin-like growth factor system gene expression and proliferation in primate myometrium.

To investigate the role of locally produced insulin-like growth factors (IGFs) in sex steroid-induced growth in the primate uterus, ovariectomized rhesus monkeys were treated with placebo (control), estradiol (E2) alone, or E2 plus progesterone (P4). After 2 weeks, uteri were removed, and serial thin uterine sections were analyzed by in situ hybridization for IGF-I, IGF-II, and IGF-I and -II receptor messenger ribonucleic acids (mRNAs) and by immunocytochemistry for the cell proliferation-specific antigen Ki-67. IGF-I and IGF-II and both IGF receptor mRNAs are coexpressed by smooth muscle cells, supporting the possibility of autocrine/paracrine IGF action in stimulating myometrial growth. IGF-I mRNA is barely detected in control myometrium, is significantly increased by E2 treatment, and is augmented even more by the combination of E2 and P4 treatment, whereas little change is noted in myometrial IGF-II or IGF-I receptor mRNA levels. Ki-67-positive myometrial nuclei are also significantly increased by E2 and are augmented even more by E2 plus P4 treatment, with a correlation between local IGF-I mRNA concentration and local Ki-67-positive cell count of r = 0.891 (P = 0.003). These data provide direct experimental evidence for regulation of IGF-I gene expression by sex steroids in the primate uterus in vivo and implicate local IGF-I action in both estrogen- and P4-induced myometrial growth.

Animals↗

PubMed1996

Cellular localization and sex steroid regulation of insulin-like growth factor binding protein messenger ribonucleic acids in the primate myometrium.

Insulin-like growth factors (IGF)-I and -II are abundant in the primate myometrium and are implicated in the sex steroid-induced growth of this tissue. To evaluate the potential for modulation of IGF action in the primate myometrium by locally produced IGF binding proteins (IGFBPs), we examined the cellular localization and sex steroid regulation of IGFBPs 1-5 in the nonhuman primate uterus. Ovariectomized rhesus monkeys were treated with placebo, estradiol (E2), or E2 and progesterone (P4) (E2 and P4) for 2 weeks, after which their uteri were removed and cut into thin serial sections for analysis by in situ hybridization. IGFBP-1 messenger RNA (mRNA) was not detected in control or E2-treated uteri but was found in a few unidentified cells in the E2 and P4-treated group. IGFBP-2, -3, -4, and -5 mRNAs were all expressed by myometrial smooth muscle cells but each displayed distinctive patterns of regulation by sex steroids. IGFBP-2 was barely detectable in control myometrium, was significantly increased by E2 and even more significantly by E2 and P4. IGFBP-4 and 5 mRNAs were readily detectable in control myometrium and significantly increased by E2 treatment. The addition of P4 to E2 treatment did not produce a significantly greater augmentation in IGFBP-4 or 5mRNA level compared with E2 alone. IGFBP-3 mRNA was abundant in the control myometrium, but in contrast to other IGFBPs was significantly reduced by approximately 75% in smooth muscle cells by E2 and by E2 and P4 treatment. Interestingly, however, IGFBP-3 mRNA was increased in the uterine vascular endothelium by E2 and by E2 and P4 treatment. In summary, this study has shown that four of the six known IGFBPs are highly expressed in the primate myometrium, and that their expression is differentially regulated by sex steroids. The cellular and sex steroid-regulated pattern of IGFBP-2 gene expression is very similar to that of IGF-I, as previously determined in these same myometrial samples. Both IGF-I and IGFBP-2 are dependent on E2 for significant myometrial expression, and both are further augmented by the addition of P4 to E2 treatment. Uterine smooth muscle IGFBP-3 mRNA levels are negatively regulated, whereas IGFBP-4 and -5 mRNA levels are positively regulated by E2: none of these myometrial IGFBPs appears sensitive to the effects of P4. The present observations, together with our previous data from the same animals, demonstrate that the primate myometrial smooth muscle cell expresses mRNAs for IGF-I and -II, IGF-I and -II receptors, as well as expresses mRNAs for IGFBP-2, -3, -4, and -5. These data provide evidence for complex local interactions between IGF system components regulated by estrogen and progesterone.

Animals↗

PubMed1995

Cryogenic spinal cord injury induces astrocytic gene expression of insulin-like growth factor I and insulin-like growth factor binding protein 2 during myelin regeneration.

To study injury-induced astrocytic responses associated with regrowth of axons and regeneration of myelin, the method of Collins and colleagues was used to make focal cryogenic lesions in spinal cords of adult rats (Collins et al.: J Neuropathol Exp Neurol 45: 742-757, 1986). The duration of cryogenic injury (CI), the size of the cryode, and its temperature were chosen to destroy all myelin sheaths and axons without producing cavities or hemorrhages. Messenger RNA and peptide distributions of insulin-like growth factor I (IGF-I), IGF-I receptor (IGFR-I), IGF binding protein 2 (IGFBP-2), glial fibrillary acidic protein (GFAP), and myelin basic protein (MBP) were studied 3-56 days after CI by in situ hybridization and immunocytochemistry. At 3 days, vimentin-positive, GFAP-negative astrocyte-like cells in the lesion expressed IGF-I mRNA and peptide and 7 days after CI, both were expressed by typical GFAP-positive, hypertrophic astrocytes, many of which also were vimentin-positive. Levels of IGF-I, IGFBP-2, and GFAP mRNA and peptide were higher in lesion astrocytes after 14 days. They attained maximum levels at 21-28 days before declining to near control levels at 56 days. Decreasing relative levels of oligodendroglial MBP mRNA were found in and around lesions 7-14 days after CI; subsequently, rising levels accompanied remyelination. At 28 and 56 days after CI, some transferrin-positive, oligodendroglia-like cells also were immunostained by anti-IGFR-I. Our findings suggest that early astrocytic production of IGF-I and IGFBP-2 may be involved in the myelin regeneration which occurs in this model of spinal cord injury.

Animals↗

PubMed1995

Distinctive anatomical patterns of gene expression for cGMP-inhibited cyclic nucleotide phosphodiesterases.

Type III cGMP-inhibited phosphodiesterases (PDE3s) play important roles in hormonal regulation of lipolysis, platelet aggregation, myocardial contractility, and smooth muscle relaxation. We have recently characterized two PDE3 subtypes (PDE3A and PDE3B) as products of distinct but related genes. To elucidate their biological roles, in this study we compare cellular patterns of gene expression for these two enzymes during rat embryonic and postnatal development using in situ hybridization. PDE3B [corrected] mRNA is abundant in adipose tissue and is also expressed in hepatocytes throughout development. This mRNA is also highly abundant in embryonic neuroepithelium including the neural retina, but expression is greatly reduced in the mature nervous system. Finally, PDE3B [corrected] mRNA is localized in spermatocytes and renal collecting duct epithelium in adult rats. PDE3B mRNA is highly expressed in the cardiovascular system, including myocardium and arterial and venous smooth muscle, throughout development. It is also abundant in bronchial, genitourinary and gastrointestinal smooth muscle and epithelium, megakaryocytes, and oocytes. PDE3A [corrected] mRNA demonstrates a complex, developmentally regulated pattern of gene expression in the central nervous system. In summary, the two different PDE3s show distinctive tissue-specific patterns of gene expression suggesting that PDE3B [corrected] is involved in hormonal regulation of lipolysis and glycogenolysis, while regulation of myocardial and smooth muscle contractility appears to be a function of PDE3A [corrected]. In addition, the present findings suggest previously unsuspected roles for these enzymes in gametogenesis and neural development.

Animals↗