Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PITUITARY GLAND”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources
PubMed1983

Thyrotropin releasing hormone-induced hyperthermia in mice: possible involvement of adrenal and pituitary glands.

To investigate the hyperthermic effect of thyrotropin releasing hormone (TRH) and its potentiation by exogenous catecholamines (CA), the role of the adrenal medulla and of the pituitary gland was studied in unoperated, adrenal-demedullated or hypophysectomized mice. In unoperated mice, TRH 40 mg kg-1 i.p. produced a hyperthermia which was accompanied by an increase in plasma noradrenaline (NA) and adrenaline (Ad). NA or Ad, both at a dose of 1 mg kg-1 i.p., enhanced the TRH-induced hyperthermia. Adrenal demedullation suppressed the hyperthermia and the increase of plasma CA produced by TRH but not the potentiation of this hyperthermia by exogenous CA. Hypophysectomy abolished the TRH-induced hyperthermia but not the increase of plasma CA or the potentiation of this hyperthermia by exogenous CA. These results suggest that, in mice, both the adrenal medulla and the pituitary gland play an essential role in TRH-induced hyperthermia but not in its potentiation.

Adrenal Glands↗
PubMed1993

Human fetuin/alpha 2 HS glycoprotein in colloid and parenchymal cells in human fetal pituitary gland.

An immunohistochemical study was undertaken, in an attempt to identify the acidic glycoprotein(s) present in colloid and in parenchymal cells in human fetal pituitary gland. As the colloid has been proposed to represent disintegrating cells, a series of antibodies against plasma glycoproteins and plasma proteins was applied; their presence intracellularly would generally be an indicator of plasma membrane leakage in dying parenchymal cells. In tissue sections from 9- to 20-week-old fetuses, the colloid showed prominent staining with an antibody to human fetuin/alpha 2 HS glycoprotein. Anti-alpha 2-HS glycoprotein labelled parenchymal cells in pars anterior and intermedia. Apart from a minor immunoreactivity for alpha 1 beta glycoprotein, no other plasma glycoprotein was seen in colloid or parenchymal cells. An antibody against bovine fetuin showed staining of the colloid and of some parenchymal cells in pars distalis and intermedia; the plasma and stroma of the pituitary gland were unstained. In contrast, the anti-human plasma protein antibodies all stained the stroma. The presence of alpha 2 HS glycoprotein in parenchymal cells and absence of other plasma glycoproteins imply integrity of the parenchymal cell plasma membrane. Thus, alpha 2 HS glycoprotein is either synthesized locally or taken up specifically in the parenchymal cells, which are proposed to participate in the formation of colloid. It is suggested that alpha 2 HS glycoprotein is part of a homeostatic system, which controls remodelling and physiological cell death during development.

Animals↗
PubMed1998

Detection of prolactin receptor gene expression in the sheep pituitary gland and visualization of the specific translation of the signal in gonadotrophs.

In sheep, as in other mammalian species, the pronounced reduction in GnRH and gonadotropin secretion that characterizes stages of infertility is normally associated with a conspicuous increase in the secretion of PRL. A possible role of PRL in modulating gonadotropin release implies the presence and activation of specific receptors in target tissues (i.e. pituitary, hypothalamus). In this study, we investigated the expression of PRL receptor (PRL-R) messenger RNA (mRNA) in the sheep pituitary and the distribution of the translated product in specific pituitary cell types. Using primers designed to flank different regions of the extracellular and cytoplasmic domains of the PRL-R, two complementary DNA (cDNA) fragments, one of which was specific for the long-form PRL-R, were amplified by reverse transcriptase-PCR. Sequencing revealed more than 95% identity with nucleotides 267-1272 of the bovine PRL-R cDNA. When these cDNA fragments were used as probes for the detection of PRL-R mRNA expression by Northern analysis, three major transcripts of approximately 13, 10, and 3.5 kb were identified in the pituitary. Both probes detected identical transcripts, suggesting that primarily the long form of PRL-R is expressed in the sheep pituitary gland. No difference in the abundance of pituitary PRL-R mRNA transcripts was observed between anestrous and breeding season ewes (P > 0.05). Additional RT-PCR studies revealed the existence of a cDNA variant bearing a 39-bp insert with a premature stop codon. Translation of the PRL-R mRNA was confirmed by Western blot analysis. The identification of PRL-R in specific pituitary cell types was carried out by immunocytochemistry. Double immunofluorescent staining, using antibodies to the rat liver PRL-R and specific monoclonal antibodies to the LHbeta-subunit, FSHbeta-subunit, free alpha-subunit, PRL, or GH, revealed that in both the pars distalis and pars tuberalis, all pituitary cells expressing PRL-R immunoreactivity were positive for LHbeta, although only 53% of LHbeta-positive cells expressed PRL-R. A small proportion (2%) of gonadotrophs expressing PRL-R immunoreactivity were negative for FSHbeta, indicating the specific localization of PRL-R in LH (or LH/FSH) secreting cells. Further, a selective cytological association was detected in the pars distalis where LH gonadotrophs appeared surrounded by lactotrophs. In contrast to these observations, PRL-R immunoreactivity was completely absent in lactotrophs and in the vast majority (>98%) of somatotrophs. In conclusion, here we show the expression of PRL-R mRNA in the sheep pituitary and the specific translation of the signal in LH (or LH/FSH) gonadotrophs. These results support the hypothesis that PRL may be involved in the regulation of gonadotropin secretion through a paracrine mechanism within the pituitary gland and that this action does not seem to be mediated by changes in PRL-R mRNA expression.

Animals↗
PubMed1987

The microcirculation of rat circumventricular organs and pituitary gland.

Blood volume, blood flow, and blood-to-tissue transfer of an amino acid in circumventricular organs, such as the median eminence and subfornical organ, and the pituitary gland of conscious rats were measured by using quantitative autoradiographic techniques and computer-assisted processing of the tissue images. Retained erythrocyte and plasma volumes observed in circumventricular organs and the anterior and neural lobes of the pituitary gland were dissimilar but in all cases greater by several times than those in cerebral grey matter; these findings suggest the presence of a dense network of high-resistance microvessels in circumventricular organs. The rate of capillary blood flow in the subfornical organ and median eminence was similar to that of grey matter, whereas blood flow in the pituitary neural lobe was several times higher than in grey matter. Thus the apparent velocity of intracapillary blood flow is much higher in the neural lobe than in the subfornical organ. Blood-to-tissue transfer of a small neutral amino acid, alpha-aminoisobutyric acid, was 200 to 700 times more rapid in circumventricular organs and pituitary neural lobe than in the inferior colliculus and caudate nucleus, structures having a blood-brain barrier (BBB). Morphometric analyses indicated that capillary volume and surface area were two times larger in the neural lobe than in the subfornical organ. Moreover, capillaries of the neural lobe and subfornical organ had numerous endothelial fenestrations and cytoplasmic pits or vesicles, whereas capillaries of the inferior colliculus had no fenestrations and fewer vesicles. These studies demonstrate quantitative differences in the microcirculatory systems not only between circumventricular organs and BBB structures but also among circumventricular organs.

Aminoisobutyric Acids↗
PubMed1985

Duplication of the pituitary gland and spinal cord.

Multiple malformations, including duplication of the pituitary gland, stalk, and infundibulum, and complex duplication of the spinal cord were observed in a female infant. The problems of classification of the spinal cord duplications are discussed, and the role of the notochord in the formation of double organs is proposed.

Abnormalities, Multiple↗
PubMed1984

Isolation of corticotropin-beta-lipotropin common precursor from ovine pituitary glands.

Ovine corticotropin-beta-lipotropin common precursor was purified to homogeneity from commercial frozen ovine pituitary glands. A crude preparation was obtained following a procedure published elsewhere (Lee, T.H. and Lee, M.S. (1977) Biochemistry 16, 2824-2829) and was purified by gel filtration on Sephadex G-200 in the presence of 0.5% SDS and 0.1% 2-mercaptoethanol, and under an atmosphere of nitrogen. The gel filtration was repeated once. The partially purified preparation obtained from the second Sephadex G-200 gel filtration was further fractionated by preparative SDS-acrylamide gel electrophoresis, using immunoprecipitated and electrophoretically purified [125I]corticotropin-beta-lipotropin common precursor as a marker. The preparation was judged homogeneous by the appearance of a single protein band in analytical SDS-acrylamide gel electrophoresis, which exhibited both corticotropin and beta-lipotropin immunoreactivities, and a single symmetrical peak in high-pressure liquid chromatography on a reverse phase C18 column. The isolated ovine corticotropin-beta-lipotropin common precursor possessed specific activities of 116 micrograms of immunoreactive corticotropin and 210 micrograms of immunoreactive beta-lipotropin per mg of protein, equivalent to 89 and 62% of theoretical values, respectively. The amino acid composition of the homogeneous preparation was determined.

Amino Acids↗
PubMed1989

Phosphorylation of a group of proteins related to the physiological, multihormonal regulations of the various cell types in the anterior pituitary gland.

We previously identified a group of cytoplasmic phosphoproteins whose phosphorylation could be related to the multihormonal regulation of PRL in the homogeneous tumor-derived GH cell lines (set of proteins 1-11) and in heterogeneous normal anterior pituitary cells in culture (set of proteins 1-15). In normal cells, a mixture of hypothalamic hormones induced, like the tumor promoter 12-O-tetradecanoylphorbol-13-acetate, stronger phosphorylation changes than TRH alone. Proteins of the set 1-15 are therefore likely to be present also in the nonmammotrophic anterior pituitary cell types, where their phosphorylation can be regulated by the hormones specific of the cell type considered. This interpretation is confirmed by the presence of the same proteins in cells of the corticotroph-like AtT-20/D16 cell line and the regulation of their phosphorylation by CRF. The same phosphoproteins were also detected in non dissociated anterior pituitary tissue from ovariectomized rats. Their phosphorylation was regulated by various hormones and other extracellular agents in a way similar to their regulation in anterior pituitary cells in culture. A 5-day estradiol implant pretreatment of the ovariectomized rats, which stimulates the anterior pituitary gland both directly and indirectly, resulted in a very high level of basal phosphorylation of proteins 1-15. Only very little further stimulation was achieved by the addition of exogenous hypothalamic hormones, indicating that the actual physiological regulatory pathways are the same as those unraveled in the various cell culture model systems. In conclusion, phosphorylation of proteins 1-15 1) can be related to the multihormonal regulation of the various anterior pituitary cell types in culture and 2) corresponds to intracellular molecular mechanisms actually involved in the physiological regulations of pituitary functions in the intact anterior pituitary gland.

Animals↗
PubMed2005

Perinatal glucocorticoid treatment produces molecular, functional, and morphological changes in the anterior pituitary gland of the adult male rat.

Stress or glucocorticoid (GC) treatment in perinatal life can induce long-term changes in the sensitivity of the hypothalamo-pituitary-adrenocortical axis to the feedback actions of GCs and, hence, in GC secretion. These changes have been ascribed largely to changes in the sensitivity of the limbic system, and possibly the hypothalamus, to GCs. Surprisingly, the possibility that early life stress/GC treatment may also exert irreversible effects at the pituitary level has scarcely been addressed. Accordingly, we have examined the effects of pre- and neonatal dexamethasone treatment on the adult male pituitary gland, focusing on the following: 1) the integrity of the acute annexin 1 (ANXA1)-dependent inhibitory actions of GCs on ACTH secretion, a process requiring ANXA1 release from folliculostellate (FS) cells; and 2) the morphology of FS cells and corticotrophs. Dexamethasone was given to pregnant (d 16-19) or lactating (d 1-7 postpartum) rats via the drinking water (1 microg/ml); controls received normal drinking water. Pituitary tissue from the offspring was examined ex vivo at d 90. Both treatment regimens reduced ANXA1 expression, as assessed by Western blotting and quantitative immunogold labeling. In particular, the amount of ANXA1 located on the outer surface of the FS cells was reduced. By contrast, IL-6 expression was increased, particularly by the prenatal treatment. Pituitary tissue from untreated control rats responded to dexamethasone with an increase in cell surface ANXA1 and a reduction in forskolin-induced ACTH release. In contrast, pituitary tissue from rats treated prenatally or neonatally with dexamethasone was unresponsive to the steroid, although, like control tissue, it responded readily to ANXA1, which readily inhibited forskolin-driven ACTH release. Prenatal dexamethasone treatment reduced the size but not the number of FS cells. It also caused a marked reduction in corticotroph number and impaired granule margination without affecting other aspects of corticotroph morphology. Similar but less marked effects on pituitary cell morphology and number were evident in tissue from neonatally treated rats. Our study shows that, when administered by a noninvasive process, perinatal GC treatment exerts profound effects on the adult pituitary gland, impairing the ANXA1-dependent GC regulation of ACTH release and altering the cell profile and morphology.

Adrenocorticotropic Hormone↗
PubMed1965

Isolation of nerve endings from the posterior pituitary gland. Electron microscopy of fractions obtained by centrifugation.

Bovine posterior pituitary glands were homogenized in 10 per cent sucrose and fractionated by differential centrifugation. The following centrifugation procedure resulted in the most satisfactory separation: 1000 g for 15 minutes-nuclei, connective tissue, basement membranes with associated endothelium, giant nerve endings, and whole pituicytes; 4200 g for 15 minutes-free nerve endings, including Herring bodies; 17,000 g for 15 minutes-mitochondria; 68,000 g for 15 minutes-neurosecretory granules. Electron microscopic examination was carried out on whole tissue and on the isolated fractions. Isolated nerve endings were examined also by negative staining techniques. Isolated nerve endings retain an apparently normal complement of mitochondria, neurosecretory granules, and microvesicles ("synaptic" vesicles). The free nerve endings closely resemble those observed in sections of intact posterior pituitary tissue. Free microvesicles were not observed in any of the fractions isolated and apparently sediment at centrifugal forces higher than those employed in this study.

Animals↗
PubMed1995

Absent pituitary gland in two brothers with an oral-facial-digital syndrome resembling OFDS II and VI: a new type of OFDS?

The oral-facial-digital syndromes (OFDS) comprise a group of heterogeneous genetic disorders. Considerable clinical overlap exists within the nine described types [Toriello, Clin Dysmorph 2:95-105, 1993], and with other entities such as Pallister-Hall (PH) syndrome and hydrolethalus syndrome, leading to difficulties in the classification of OFDS. We report on two brothers with findings overlapping OFDS II, VI, and Pallister-Hall syndrome who had congenital absence of the pituitary gland. This may represent a new type of OFDS or, alternatively, an example of phenotypic variability within the OFDS. It also emphasizes that agenesis of the pituitary gland can occur in a variety of syndromes with midline defects.

Face↗
PubMed2005

Distribution of immunoreactivities for adenohypophysial hormones in the pituitary gland of the polypteriform fish, Polypterus endlicheri.

Polypteriform fish constitutes the most primitive living descendent of the ancient bony fish. In polypteriform fish, only proopiomelanocortin (POMC) has been identified so far in the adenohypophysis, which is surprising in view of their evolutionary importance. In the present study, distribution of immunoreactive adenohypophysial hormones was examined in juvenile individuals of Polypterus endlicheri. Antisera to tetrapod and fish adenohypophysial hormones were used as immunostaining probes. Adrenocorticotropin (ACTH)-like cells were detected by antisera to salmon POMC N-terminal peptide, porcine ACTH and mammalian alpha-melanotropin (MSH), and were distributed in the rostral pars distalis in close proximity to the hypophysial duct. MSH-like cells were found in the pars intermedia, and were stained by anti-salmon N-Ac-beta-endorphin II as well as anti-mammalian alpha-MSH and anti-salmon POMC-N terminal peptide. Prolactin (PRL)-like cells were detected only after application of anti-sturgeon PRL, and were distributed in the rostral pars distalis, where PRL-positive material was found in columnar mucinous cells lining the diverticuli of the hypophysial duct. Growth hormone (GH)-like cells were stained with antisera to sturgeon GH, human GH, salmon GH and blue shark GH, and were distributed in the proximal pars distalis. Somatolactin (SL)-like cells were stained with anti-salmon SL, and were distributed in the pars intermedia. Two types of glycoprotein hormone-positive cells were detected in the proximal pars distalis. Although both types of cells were stained with several antisera to glycoprotein hormones, such as sturgeon LHbeta and salmon LHbeta, it was difficult to know which types of cells produce LH, FSH, or TSH. Thus, the present study revealed seven types of adenohypophysial hormone-like cells in the Polypterus pituitary gland, which may provide the morphological basis for better understanding on evolution of the pituitary gland and the adenohypophysial hormones in vertebrates.

Animals↗
PubMed2005

A calcium binding protein, calbindin-D9k, is mainly regulated by estrogen in the pituitary gland of rats during estrous cycle.

As a member of family of cytosolic calcium binding proteins, Calbindin-D9k (CaBP-9k) is expressed in female reproductive system and regulated by steroid hormones, estrogen (E2) and progesterone (P4), but its expression and role in pituitary gland have not been elucidated yet. Thus, in this study, we elucidated the expression of CaBP-9k mRNA and protein in pituitary gland of rats. During estrous cycle of rats, pituitary CaBP-9k level fluctuated, and its mRNA was highly elevated during an E2-dominant stage (proestrus and estrus), whereas its level disappeared at a P4-dominant stage (metestrus and diestrus). In parallel with CaBP-9k mRNA, an increased level of CaBP-9k protein was observed during proestrus and estrus, suggesting that pituitary CaBP-9k may be up-regulated by E2. In addition, spatial CaBP-9k expression was attested by immunohistochemistry. Pituitary CaBP-9k protein was localized in the cytoplasm of a specific cell type in the anterior lobe, and the positive cells were abundant at proestrus and estrus. The CaBP-9k-positive cells were mainly localized in the acidophils producing growth hormones and prolactin. To verify hormonal regulation of pituitary CaBP-9k in this tissue, immature rats were treated with a physiological dose of E2 in the absence or presence P4 for 3 days. In a time-dependent experiment, pituitary CaBP-9k protein was induced at 48 h after the final E2 injection. A significant increase in CaBP-9k protein was caused by E2, whereas P4 antagonized E2-stimulated CaBP-9k expression as similarly observed in the uterus. Taken together, these results indicated for the first time that pituitary CaBP-9k expression is regulated during estrous cycle, and its expression is mainly controlled by E2 and antagonized by P4, suggesting that pituitary CaBP-9k in female rats may be involved in the central function of the reproduction system.

Animals↗
PubMed1989

Bromocriptine-responsive Cushing's disease associated with anterior pituitary corticotroph hyperplasia or normal pituitary gland.

Cushing's disease may originate from either the anterior pituitary lobe or the neurointermediate lobe, a major characteristic of the latter group being bromocriptine responsiveness. This study of two patients with Cushing's disease demonstrates that bromocriptine responsiveness also may be associated with anterior pituitary corticotroph hyperplasia or a normal pituitary gland. The two patients were a 14-yr-old boy (patient 1) and a 29-yr-old woman (patient 2); their cortisol production rates were 121 and 234 mumol/24 h (normal values, less than 80 mumol/24 h), respectively. A single oral dose of 2.5 mg bromocriptine resulted in a gradual decrease in plasma cortisol from 680 to 130 nmol/L after 6 h in patient 1 and from 640 to 170 nmol/L after 4 h in patient 2. Both patients then received medical treatment for a period of 2 yr. Whereas sodium valproate was ineffective, bromocriptine (5 mg/day) abruptly decreased the cortisol production rate to 60 mumol/24 h in patient 1 and to 138 mumol/24 h in patient 2, and both patients had a partial clinical remission. Despite an increase in bromocriptine dosage to 30 mg daily and 24 mg/day cyproheptadine, the clinical and biochemical remission was not sustained in patient 1, and no further improvement occurred in patient 2. Total hypophysectomy then was performed in both patients. Sections of the pituitary from patient 1 showed diffuse anterior pituitary corticotroph hyperplasia, with early nodule formation in some areas. The sections from patient 2 showed normal numbers and distribution of corticotrophs. We conclude that the heterogeneous nature of Cushing's disease cannot be explained on the basis simply of anterior vs. intermediate lobe origin of the disease.

Adolescent↗