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Biomedical subjects

D Schams

Publications and source records attributed to D Schams.

At least 55 records · Page 3Linked to original sources
PubMed2000

Cellular localization of fibroblast growth factor 2 (FGF-2) in benign prostatic hyperplasia.

Fibroblast growth factor 2 (FGF-2, basic fibroblast growth factor) has been reported to be elevated in tissues from benign prostatic hyperplasia (BPH), the most frequent neoplastic disease in aging men. This suggests that FGF-2 may play a significant role in the development of BPH. In this study the cellular distribution pattern of FGF-2 in tissues from BPH has been investigated by immunohistochemical and molecular biological methods. Radioimmunoassay revealed high concentrations of FGF-2, ranging between 450 and 950 ng per g tissue. Immunoblots confirmed the presence of a 18 kDa FGF-2 in tissue extracts. By immunohistochemistry done with a polyclonal antibody to recombinant FGF-2 on paraffin sections, FGF-2 was localized in fibroblasts, endothelial cells and smooth muscle cells of tissue samples of BPH. Nuclei of these cells were labelled distinctly. Moreover the cytoplasm of smooth muscle cells was labelled moderately. No immunostaining was seen in prostatic epithelium. Non-radioactive in situ hybridization with digoxygenin-labelled oligonucleotides revealed the presence of mRNA for FGF-2 in smooth muscle cells of the prostatic stroma. These results provide evidence that FGF-2 may be produced locally in the human prostate as a stroma-specific mitogen and may play a causal role in the development of BPH.

Fibroblast Growth Factor 2↗
PubMed2000

Cyproterone acetate reduced antler growth in surgically castrated fallow deer.

We studied the role of androgens in antler growth. In particular, we investigated whether the onset of antler regrowth is triggered by a short-term pulse of testosterone and if low levels of androgens are required for antler growth. The study was conducted on 12 surgically castrated fallow deer bucks (Dama dama) aged approximately 27 months. Six animals (CA group) were given the antiandrogen, cyproterone acetate (CA, 1000 mg/treatment); the others were given vehicle solution only (control). Before each CA treatment, blood was sampled and analysed for testosterone, androstenedione, IGF-1, cortisol, FSH, and LH. CA treatment and blood sampling were performed 2 days before castration, on the day of castration and afterwards at 2-day intervals until day 22. Subsequently, CA treatment and blood sampling continued at weekly intervals until day 270. All animals cast their antlers, followed by antler regrowth in all control bucks, but in only four of the six CA-treated castrates. Plasma testosterone concentrations were low in all animals (between 0.01 and 0.20 ng/ml), but were significantly (P<0001) greater in the controls. In both groups, a temporary increase in testosterone values was recorded around the time of antler regrowth, the peak being significantly (P<0.01) higher in the controls. Androstenedione showed a similar pattern as testosterone. Plasma IGF-1 concentrations increased sharply during the antler growth spurt and did not differ significantly between the two groups throughout the study period. Cortisol concentrations were greater in controls than in the CA group. However, no link with the antler cycle was apparent. FSH and LH concentrations were higher in the controls for most of the study. Antlers produced by the control bucks were significantly larger than those in the CA group (P<0.03). For antler length, testosterone, androstenedione and IGF-1, areas under the curve (AUC) were calculated over the period of antler growth. For the pooled deer (n=12) significant correlations existed between AUCs of antler length and testosterone, but not for antler length and IGF-1. Also, a trend for a positive correlation between AUCs of antler length and androstenedione was noted. It is concluded that a plasma androgen concentration at least above a minimal threshold level is a necessary prerequisite for normal antler regrowth in fallow deer, and that this androgen effect is not mediated via circulating IGF-1. The biological role of low levels of androgens may be to sensitize antler cells to the stimulating effect of IGF.

Androgen Antagonists↗
PubMed2000

Cellular localisation of GH receptor in the bovine mammary gland during mammogenesis, lactation and involution.

We have used immunohistochemistry and non-radioactive in situ hybridisation to localise the GH receptor and its transcript in the bovine mammary gland during mammogenesis, lactation and involution. We found a characteristic pattern of immunoreactive GH (irGH) receptor distribution in the epithelial and stromal compartments during the different stages of mammary gland development: The ductular epithelium showed a distinct staining for irGH receptor during most stages, whereas the alveolar epithelium contained a modest amount of GH receptor during pregnancy which increased during lactation and galactopoiesis. In dry cows, the immunostaining for GH receptors in the alveolar epithelium was very weak or negative. Curiously, the amount of GH receptor mRNA appeared relatively constant during mammogenesis and lactation. The epithelial cells of the alveoli and ducts as well as the endothelial cells showed a distinct signal in our in situ hy! bridisation studies. The predominant localisation of GH receptors in the epithelium of ducts and alveoli is supportive of a role for GH in epithelial differentiation and maintenance. Furthermore, the increased intensity of immunostaining in bovine mammary tissue post partum suggests a direct role for GH receptor in mediating the effect of GH in milk production and secretion.

Animals↗
PubMed2000

Expression and localisation of vascular endothelial growth factor and basic fibroblast growth factor during the final growth of bovine ovarian follicles.

Locally produced growth factors may have important modulatory roles in final ovarian follicular growth. The aim of this study was to investigate the possible participation of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF2) in bovine follicles during final growth. Ovaries were collected from a slaughterhouse within 10-20 min after exsanguination. A classification of follicles into five groups (<0.5; >0.5-5; >5-20; >20-180; >180 ng/ml) was performed according to the follicular fluid (FF) oestradiol-17 beta content. For a better characterisation of classes the mRNA expressions of FSH receptor, LH receptor and aromatase cytochrome P450 in theca interna (TI) and granulosa cells (GC) were determined. Analysis of VEGF transcript by RT-PCR showed that GC and theca cells express predominantly the smallest isoforms (VEGF(121) and VEGF(165)). VEGF mRNA expression in both tissues (TI and GC) and VEGF protein concentration in total follicle tissue increased significantly (and correlated) with developmental stages of follicle growth. The expression of mRNA for VEGF receptor (VEGFR)-1 and VEGFR-2 was very weak in GC, without any regulatory change during final follicle growth. In contrast, TI showed strong expression of mRNA for both receptors in all follicle classes examined. VEGF protein concentrations in FF increased significantly and continuously to maximum levels in preovulatory follicles. As shown by immunohistochemistry, VEGF protein was clearly localised in TI and GC of preovulatory follicles. FGF2 and FGF receptor (FGFR) mRNA expression in TI increased significantly during final growth of follicles. In contrast, the FGF2 and FGFR mRNA expression in GC was very weak and without any regulatory change during follicle growth. Histological observation revealed that FGF2 protein was localised in theca tissue (cytoplasm of endothelial cells and pericytes) but not in GC. Our results suggest that VEGF and FGF families are involved in the proliferation of capillaries that accompanies the selection of the preovulatory follicle resulting in an increased supply of nutrients and precursors, and therefore supporting the growth of the dominant follicle.

Analysis of Variance↗
PubMed1999

Expression of vascular endothelial growth factor (VEGF) and its corresponding receptors (flt-1 and flk-1) in the bovine oviduct.

Vascular endothelial growth factor (VEGF) functions as a potent angiogenic protein as well as in regulating permeability. Reverse transcription-polymerase chain reaction (RT-PCR) and ribonuclease protection assay (RPA) were used to show that the bovine oviduct expresses VEGF and its two receptors flk-1 and flt-1. Expression of VEGF was relatively stable during the estrous cycle. In contrast, both receptor transcripts showed cycle-dependent variations with significantly increased flt-1 mRNA amounts before ovulation. Immunohistochemical studies localized VEGF mainly on the epithelial surface of oviducts. Protein concentrations of VEGF in oviductal flushings were significantly higher (mean +/- SEM: 2.8 +/- 0.8 ng/ml) during the pre-ovulatory phase when compared with the other estrous cycle stages (1.0 +/- 0.25 ng/ml). In conclusion, all components of a functional VEGF-system in the bovine oviduct were found to undergo specific modulations during the cycle. We suggest that VEGF may be involved in creating an optimal local environment for fertilization or the developing embryo by modulating permeability within the bovine oviduct.

Animals↗
PubMed1999

Possible role of growth hormone, IGFs, and IGF-binding proteins in the regulation of ovarian function in large farm animals.

The aim of the study and short review was to present evidence that growth hormone (GH), locally produced insulin-like growth factors (IGFs), and IGF-binding proteins (IGFBPs) may have an important role in the control of ovarian function. There is clear evidence for a distinct GH-receptor mRNA expression and protein production in follicles (oocytes and granulosa-cumulus cells) and corpus luteum (CL). In hypophysectomized ewes, GH and LH are necessary for normal CL development. IGF-1 mRNA in the follicles is expressed in theca interstitial cells (TIC) and granulosa cells (GC) with already higher levels in the TIC before follicle selection. In contrast, IGF-2 is mainly expressed in the TIC. The IGFR-1 mRNA is expressed in both the TIC and GC, with increasing levels in GC during the final development of dominant follicles. IGF-1 is a very potent stimulator of progesterone and oxytocin release in GC. IGFBP-1, -2, -3, -4, -5, and -6 have been isolated from follicular fluid or ovarian tissue. Studies indicate that IGFBP expression and production in the developing follicle is dependent on both cell type and follicle size and is regulated by IGF-1 and gonadotropins. The highest expression of IGF-1 and IGFR-1 mRNA was demonstrated during the early luteal phase. Distinct receptors for IGF-1 and IGF-2 were present in CL membrane preparations at all stages investigated. Intense immunostaining for IGF-1 was observed mainly in bovine large and small luteal cells and in a limited number of endothelial cells. In contrast, IGF-2 protein was localized in perivascular fibroblast and pericytes of the capillaries. With the use of a microdialysis system, we found that in vitro and in vivo IGF-1, IGF-2, and GH stimulated the release of progesterone in cultures of luteal cells or intact tissues. In conclusion, there is clear evidence for a central role of the IGFs, IGFBPs, and GH in follicular development and CL function.

Animals↗
PubMed1999

The effect of ACTH on the GnRH-induced release of LH and testosterone in male white-tailed deer.

In order to investigate the possible link between stress and the impairment of the reproductive system, 12 yearling white-tailed bucks, born to mothers captured wild in southern Texas, were immobilized every 6 weeks over the period of 1 year. In half of experiments deer were injected i.m. with 20 i.u. of ACTH; in the second half, we used saline only. Simultaneously, in each experiment we also injected all deer i.m. with 100 micrograms of GnRH. Three blood samples were taken before and seven after treatment and plasma levels of cortisol, LH and testosterone (T) were later measured by RIA. Half of our yearlings were born to mothers which were fed high-protein-high-energy (HP-HE) diet during their pregnancy; the other half ws fed high-protein-low-energy diet (HP-LE). ACTH increased cortisol levels in both nutritional regimes. Cortisol levels in controls decreased with time but a more pronounced reduction was observed in HP-HE bucks as compared to HP-LE deer. GnRH significantly increased LH and T levels. However, only in summer, LH levels were higher in HP-LE fed deer than those fed HP-HE; in other seasons they were equal. Conversely, only in winter T levels were elevated in HP-HE fed deer as compared with HP-LE deer. We concluded that the pronounced suppression of reproductive hormones by ACTH or cortisol reported previously in domestic ungulates does not occur in white-tailed deer yearlings. Conversely, the low level of energy provided in food to mothers during their pregnancies significantly reduced peak levels of testosterone in their male offspring. This study further proved that white-tailed deer is a highly adaptable cervid species resistant to environmental stress.

Adrenocorticotropic Hormone↗
PubMed1999

Tumor necrosis factor alpha receptors in microvascular endothelial cells from bovine corpus luteum.

There is sufficient evidence to prove that tumor necrosis factor alpha (TNFalpha) modulates bovine corpus luteum (CL) function. Our previous study demonstrated that functional TNFalpha receptors are present on luteal cells in bovine CL throughout the estrous cycle. The purpose of the present study was to identify the presence of functional TNFalpha receptors on the microvascular endothelial cells derived from developing bovine CL. TNFalpha receptors were analyzed by a radioreceptor assay using (125)I-labeled TNFalpha on two types of cultured endothelial cells. One has a cobblestone appearance (CS cells), and the other has a tube-like structure (TS cells). (125)I-Labeled TNFalpha binding was maximal after incubation for 30 h at 37 degrees C, and the specificity of binding was confirmed. A Scatchard analysis showed the presence of two binding sites (high- and low-affinity) for TNFalpha receptors on both CS and TS cells. The dissociation constant (K(d)) values and concentrations of the high-affinity binding sites for TNF receptors were similar for CS and TS cells. However, K(d) values and concentrations of the low-affinity binding sites in CS cells were significantly higher than those in TS cells (P < 0.05 or lower). The expression of TNF receptor type 1 (TNF-RI) mRNA was determined in both cell types. Furthermore, TNFalpha significantly stimulated prostaglandin E(2) and endothelin-1 secretion by both CS and TS cells (P < 0.05 or lower). These results indicate the presence of two types of TNF receptors and the expression of TNF-RI mRNA in the endothelial cells derived from bovine CL, and suggest that TNFalpha plays two or more roles in regulating the secretory function of the endothelial cells.

Animals↗
PubMed1999

Evidence for a local endothelin-angiotensin-atrial natriuretic peptide systemin bovine mature follicles in vitro: effects on steroid hormones and prostaglandin secretion.

Recent evidence suggests the presence of a functional endothelin-angiotensin-atrial natriuretic peptide system at the ovarian level. This study aimed to investigate 1) the local interrelationships among angiotensin II (Ang II), endothelin-1 (ET-1), and atrial natriuretic peptide (ANP); 2) the possible effect of each vasoactive peptide on the secretion of steroid hormones and prostaglandins (PGs) in isolated bovine mature follicles; and 3) the expression of mRNAs for Ang II, ET-1, and ANP receptors in the theca layer of follicles at different developmental stages. Each preovulatory follicle obtained before the LH surge (based on the concentrations of steroids and PGs) received implants of 4 capillary dialysis membranes into the theca layer. The follicles were then incubated in organ culture chambers and perfused with Ringer's solution for 12 h. Stimulation by infusion of the different substances into the microdialysis system was carried out between 4 and 8 h. The infusion of ET-1 (10(-7) M) stimulated the release of ANP and estradiol but inhibited the release of androstenedione and progesterone. The infusion of ANP (10(-7) M) stimulated the release of Ang II, progesterone, and androstenedione. Moreover, the infusion of Ang II (10(-5) M) inhibited the release of ANP but stimulated the release of ET-1, progesterone, and estradiol. All three peptides examined increased PGE(2) and PGF(2) release. In the reverse transcription-polymerase chain reaction analysis, expression of the mRNAs for ET type A and type B, and Ang II type 1 receptors did not change with the follicular size and the intrafollicular estradiol concentrations. Expression of the mRNA for the Ang II type 2 receptor dropped in follicles when the estradiol concentration ranged from 20 to 180 ng/ml and increased again when the estradiol concentration was > 180 ng/ml. The levels of expression of ANP type C receptor mRNA were slightly greater in follicles with estradiol concentrations > 20 ng/ml than in follicles with estradiol concentrations < 20 ng/ml. These results demonstrate a complex interaction among Ang II, ET-1, and ANP that may contribute to increasing the follicular production of PGs and modulate steroidogenesis in the bovine mature follicle, thus providing evidence for a local functional endothelin-angiotensin-ANP system.

Androstenedione↗
PubMed1999

PGFM response to exogenous oxytocin and determination of the half-life of oxytocin in nonpregnant mares.

We investigated the half-life of oxytocin in reproductively normal mares and the prostaglandin response after oxytocin administrations. Mares were given oxytocin, 10 or 25 iu, i.v., on the day of, or 2 days after, ovulation, and frequent jugular blood samples were collected for analysis of oxytocin and Prostaglandin F metabolite (PGFM) by RIA. Neither dose of oxytocin nor day of treatment affected the half-life of the exogenous oxytocin, which was determined to be 6.8 min. A significant increase in PGFM was observed within 6 min of oxytocin administration and peak values were observed within 10 min. PGFM response after oxytocin administration on the day of ovulation appeared elevated compared to the response 2 days after ovulation.

Animals↗
PubMed1999

Growth factors and extracellular matrix proteins in interactions of cumulus-oocyte complex, spermatozoa and oviduct.

The expression and localization of selected growth factor systems and extracellular matrix (ECM) components that may influence oocyte maturation and fertilization within the mammalian oviduct are reported. Fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) systems could be detected by use of RT-PCR, RNase protection assay (RPA) and immunohistochemistry in bovine follicles, bovine cumulus-oocyte complexes (COC) and bovine and marmoset oviducts. Two different subtypes of the FGF receptor (FGFR-1 and -2) were identified in distinct cell types, indicating a functional difference. A complete epidermal growth factor (EGF) system was found in the porcine, but not in the bovine, oviduct. There were additional differences between bovine and primate oviducts: FGF-1/2 and FGFR were increased in the marmoset around ovulation, in contrast to an increase in FGF-1 in the cow. Immunohistochemistry revealed accumulation and storage of FGF and VEGF on the surface of the epithelium, possibly due to their binding property on heparanglycoproteins. Other ECM components, matrix metalloproteinase 1 (MMP-1) and tissue inhibitor of metalloproteinase 1 (TIMP-1), were found to be modulated in the ovarian follicle, COC and oviduct during the cycle. An oviduct-mediated depletion of sperm surface proteins (BSP1-3) was discovered as well as a sperm-induced novel oviductal mRNA related to an anti-oxidant protein family. Associated systems of growth factors and ECM components can be suggested as paracrine or autocrine mediators during fertilization in a species-, cycle- and tissue-dependent manner.

Animals↗
PubMed1998

Development of a sensitive enzymeimmunoassay for oxytocin determination in bovine plasma.

A highly sensitive and specific second antibody enzymeimmunoassay (EIA) on microtiterplates for oxytocin determination in bovine plasma using the biotin-streptavidin amplification system was developed. Biotin was coupled to oxytocin and used to bridge between streptavidin-peroxidase and the immobilized oxytocin antiserum in the competitive assay. The assay was carried out directly in 200 microliters of bovine plasma. Oxytocin standards prepared in hormone-free plasma were used. The sensitivity of the assay was 0.25 pg/well which corresponded to 1.25 pg/ml plasma; the 50% relative binding was seen at 2.8 pg/well. Plasma volumes for the assay ranging from 50 to 200 microliters did not influence the shape of the oxytocin standard curve; however a distinct drop in the OD450 was observed with higher plasma volumes. The oxytocin antiserum used in the assay showed no significant cross-reaction with other octapeptides tested. The assay was compared with a radioimmunoassay (RIA) procedure employing prior solvent extraction of plasma samples. The oxytocin concentrations assayed by EIA and RIA in plasma samples obtained from four cows before, during and after milking were highly correlated and very similar (r = 0.97). Hence the assay developed offers an attractive alternative to the RIA since no prior laborious plasma extraction is needed. Further, the assay has the distinct advantage of being non-radioactive in nature.

Animals↗
PubMed1998

Seasonal levels of metabolic hormones and substrates in male and female reindeer (Rangifer tarandus).

Seasonal levels of cortisol, growth hormone (GH), insulin like growth factor 1 (IGF-1), glucose, triiodothyronine (T3), free T3, thyroxine and free fatty acids (FFA) were measured every 3 weeks for 54 weeks in the plasma of five adult bulls, and four barren and five pregnant Alaskan reindeer (Rangifer tarandus) cows. Three consecutive samples were taken from each animal. Cortisol levels exhibited wide seasonal variation (9-45 ng/ml) [corrected] without any peak or difference in levels among groups. Rising levels were detected between the 3 consequent samples. Peak GH levels, detected during January and February, were higher in the non-pregnant group (54 ng/ml) than the pregnant (26 ng ml-1) and the male (27 ng ml-1) groups. Low GH levels (2-10 ng ml-1) were recorded between May and September. IGF-1 reached peak levels (715 ng ml-1) in males in August, in non-pregnant females in September (677 ng ml-1), and in the pregnant females in October (505 ng ml-1). Seasonal minima (404 in males, 172 and 93 in pregnant and non-pregnant groups) were detected in February. Glucose was fairly stable throughout the year (100-200 mg/100 ml). A rising levels were found between the three consecutive samples. Triiodothyronine (T3) (2.16-2.30 ng ml-1) peaked in all three groups during the spring and early summer, and minimal levels (0.61-0.97 ng ml-1) were detected from October to January. Conversely, thyroxine or free T3 did not exhibit seasonal variation. FFA fluctuated widely (97-1076 nmol l-1) throughout the year. Only in pregnant females were concentrations more stable (150-460 nmol l-1). Perhaps, because of ad libitum supply of food in captive reindeer, only T3 and GH exhibited pronounced seasonal fluctuations which could be related to the metabolic changes expected during the annual cycle.

Alaska↗
PubMed1998

Rank dependent seasonal levels of IGF-1, cortisol and reproductive hormones in male pudu (Pudu puda).

We tested the following hypothesis: when two pudu males share a single pen throughout the year, the dominant animal will have a higher level of IGF-1 than its subordinate pen mate, particularly during the period of increased social friction (e.g. rut and establishment of territories). To test this hypothesis, we used data from six adult males maintained at the University of Concepión, Chile (latitude 36.6 degrees S), and analysed them from the males' dominance point of view. Two males plus eight to ten females were kept in one pen and although we did not specifically measure dominance, the rank position was obvious from frequent encounters between the bucks. Three consecutive blood samples were taken monthly over the period of 1 year. In addition to IGF-1, we also analysed seasonal levels of testosterone, cortisol, prolactin, LH and FSH. The analysis revealed that IGF-1 levels of dominant males were significantly higher than those of subordinate males from September to November (the second part of the antler growing period and time of establishing territories). Testosterone levels were higher and FSH levels were lower in dominant males during the rut. Levels of prolactin were higher in dominant animals in November (summer). Cortisol and LH did not show any significant differences between dominant and subordinate males. This data provides the first evidence indicating the possible link between dominance and blood levels of IGF-1. The functional explanation of such links is discussed.

Animals↗
PubMed1998

Growth factors in milk: interrelationships with somatic cell count.

Growth factors are thought to play a decisive role in the course of inflammatory processes. The aim of the present study was to characterize a potential interrelationship between the concentrations of insulin-like growth factor-1 (IGF-1), basic fibroblast growth factor (bFGF) and somatic cell count (SCC) in normal milk, and to investigate the presence of these growth factors in mammary secretions of cows suffering from clinical and subclinical mastitis. Quarter secretions of cows with spontaneous acute clinical mastitis and of cows with subclinical mastitis were analysed radioimmunologically for their concentrations of IGF-1 and bFGF. During two relocation trials with normally lactating Brown Swiss cows, dramatic changes in milk somatic cell count were obtained following a short-term change (5 d) of location and housing system. The animals were relocated from their familiar loose housing system with concrete slatted floor to a separate stanchion barn with long stalls and straw bedding, and vice versa. The concentration profile of IGF-1, but not of bFGF, corresponded well with SCC during the relocation trials, the positive correlation between the characteristics being highly significant, as determined by regression analysis (r = 0.60; P < 0.001). The results provide evidence that significant changes in SCC and growth factor content may be caused by environmental factors other than infection. The concentrations of both IGF-1 and bFGF were greatly elevated in secretions of quarters affected by acute clinical mastitis compared with the corresponding clinically healthy quarters. Subclinically affected quarters with high SCC, as compared with non-affected quarters with low SCC, also had elevated milk IGF-1, but unchanged bFGF. Measuring of growth factor profiles in milk may have value in the near future in monitoring the state of udder health in addition to SCC.

Animals↗
PubMed1998

Stable production of human insulin-like growth factor 1 (IGF-1) in the milk of hemi- and homozygous transgenic rabbits over several generations.

One transgenic rabbit line was generated carrying a fusion gene consisting of the cDNA for human IGF-1 fused to a mammary gland specific expression cassette derived from bovine alpha-S1-casein sequences. Transgene expression was shown to be strictly tissue and lactation period specific. The transgenic rabbit line was bred for six generations. All transgenic animals showed stable production of biologically active IGF-1 over the generations and no apparent effect on the physiological or reproductive performance was observed. The absence of adverse effects on homozygous transgenic rabbits suggested the absence of insertional mutagenesis. Eight hemizygous transgenic offspring analysed produced on average 363 +/- 12 micrograms/ml (ranging from 223 +/- 61 to 484 +/- 39 micrograms/ml) mature human IGF-1 in their milk, whereas three homozygous animals produced on average 543 +/- 41 micrograms/ml (ranging from 360 +/- 15 to 678 +/- 80 micrograms/ml). Homozygous hulGF-1 females clearly showed a significantly increased production performance of the recombinant protein.

Animals↗
PubMed1998

Expression and localization of members of the fibroblast growth factor family in the bovine mammary gland.

The goal of the study was to examine the expression and localization of members of the fibroblast growth factor family in the bovine mammary gland during different developmental and functional stages. Mammary tissue was obtained from German Brown Swiss cows (n = 23) during defined stages of mammogenesis (before and during pregnancy), lactogenesis, peak and late lactation, and involution. Extracted mRNA was analyzed by reverse transcription polymerase chain reaction and RNase protection assay. The tissue content of fibroblast growth factor-1 and fibroblast growth factor-2 was determined by radioimmunoassay, and the localization of fibroblast growth factor-2 was determined by immunohistochemistry. The highest mRNA concentration for fibroblast growth factor-1, -2, and -7 and their receptors was detected in the glands of virgin heifers or primigravid heifers during involution; less abundant fibroblast growth factor mRNA was detected during lactogenesis and galactopoiesis. Tissue protein concentrations of fibroblast growth factor-1 and fibroblast growth factor-2 showed similar tendencies. Immunoreactive fibroblast growth factor-2 was observed during mammogenesis and involution in endothelial cells, ductal epithelial cells, myoepithelial cells, and some alveolar cells. After positive staining, fibroblast growth factor-2 could only be observed in endothelial and myoepithelial cells during lactogenesis and could only be observed in myoepithelial cells during galactopoiesis. Expression, tissue concentration, and distinct localization suggest that fibroblast growth factors may be important in the local regulation of the bovine mammary gland.

Animals↗