Rat ventral prostate as an independent source of inhibin-like material

Castration had no effect on prostatic inhibin-like activity as compared to normal controls. Consequent upon castration there is a significant reduction in the inhibin content of the ventral prostate on a per gland basis. However, when expressed as a function of protein content, there is no change. The data suggest that the very same epithelial cells which under the influence of androgen carry out the characteristic exocrine secretory activity are responsible for the synthesis and secretion of inhibin-like material.     

Antiprogestagen RU486 prevents the LH-dependent decrease in the serum concentrations of inhibin in the rat

Summary 1. In the rat, the LH-dependent ovarian progesterone rise mediates several actions of the primary surge of LH on the ovary. This experiment was aimed at elucidating the effects of the antiprogestagen RU486 on the LH-dependent decrease in both the serum concentrations and the ovarian content of inhibin.2. All rats in this experiment were treated with an antagonist of LHRH (1 mg/200 µl saline at 0800 h in proestrus) to supress the endogenous release of LH. One group of rats received 32 µg LH/250 µl saline at 1200 h in proestrus. Other group was given 4 mg RU486/200 µl oil at 0800 h in proestrus. The third group was injected with both RU486 and LH. Rats from the control group were injected with 250 µl saline and 200 µl oil. Animals were decapitated at 1700 h in proestrus and trunk blood and ovaries collected to determine the serum concentrations of LH, FSH, progesterone, 17ß-estradiol and inhibin as well as the ovarian content of inhibin.3. The ovulatory dose of LH in LHRHa-treated rats decreased both the serum concentrations and the ovarian content of inhibin and increased the serum concentrations of FSH. The administration of RU486 blocked the effect of LH on the serum concentrations of inhibin but not that on the ovarian content of inhibin.4. Since the antiprogestagen RU486 blocked the effect of LH on the serum concentrations of inhibin, we conclude that ovarian progesterone, besides mediating the effects of the primary LH surge on the ovulatory process and luteinization, participates in the LH-dependent drop in the serum concentrations of inhibin in proestrous afternoon.     

Elevated ovarian expression and serum concentration of α inhibin in the luteal phase during follicular development in the squirrel monkey (Saimiri boliviensis) compared to the human

The goal of the present investigation was to determine in the squirrel monkey the source and pattern of inhibin, a hormone known to effect reproductive steroid levels via pituitary and ovarian mechanisms. Since this seasonally polyestrous species is known to have elevated serum levels of reproductive steroids compared to other primates, the levels of ovarian alpha subunit mRNA expression and serum total alpha inhibin, estradiol, progesterone, and luteinizing hormone were measured and compared to human levels. Expression of the alpha subunit was robust in monkey luteal tissue compared to expression in human luteal tissue. Squirrel monkey serum inhibin peaked 4 days after the luteinizing hormone surge and correlated with progesterone changes. These luteal serum levels of inhibin were greater than 12 times higher than the human levels yet bio‐LH activities were less than in the human during the luteal phase. Inhibin concentrations during the non‐breeding season were generally half the levels measured in the breeding season and undetectable in ovariectomized animals. However, exogenous FSH stimulation induced a marked rise in inhibin, which correlated with an estradiol rise. In conclusion, abundant alpha inhibin subunit expression in the luteal ovary of the squirrel monkey and loss of serum delectability in ovariectomized animals indicates that the principle source of inhibin in the squirrel monkey is the ovary. Elevated serum inhibin levels during the luteal phase concurrent with ovulatory‐size follicular development is unique among species studied thus far. Possible simultaneous inhibin production from both follicular and luteal tissue may be responsible for the exceptionally high inhibin levels. Am. J. Primatol. 47:165–179, 1999. © 1999 Wiley‐Liss, Inc.     

Cloning,sequencing, and expressional analysis of the chick homologue of follistatin

Follistatin, a secreted glycoprotein, has been shown to act as a potent neural inducer during early amphibian development. The function of this protein during embryogenesis in higher vertebrates is unclear, and to further our understanding of its role we have cloned, sequenced, and performed an in-depth expressional analysis of the chick homologue of follistatin. In addition we also describe the expression pattern of activin βA and activin β B, proteins that have previously been shown to be able to interact with follistatin. In this study we show that the expression of follistatin and the activins do not always overlap. Follistatin was first detected in Hensen's node and subsequently in the region described by Spratt [1952] as the neuralising area. In older embryos it was also expressed in a highly dynamic manner in the hind-brain as well as in the somites. We also present evidence that follistatin may have a later role in the resegmentation of the somites. We were unable to detect the expression of activin βA during early embryogenesis, whereas activin βB was first expressed in the extending primitive streak and subsequently in the neural folds. The results from this study are consistent with a role for follistatin in neural induction but suggest it has additional functions unrelated to its inhibitory actions on activins. © 1995 Wiley-Liss, Inc.     

An epidemiological study of reproductive function biomarkers in male welders

In a cross-sectional study, the serum concentrations of inhibin B and prolactin of 96 male current welders were compared with the concentrations measured in 96 age-matched referents. Also, 23 patients who were all former welders diagnosed as having welding-related manganism were studied. The current welders' geometric mean (GM) airborne exposure to manganese (Mn) was 121 µg m^-3 (range 7-2320). The serum concentrations of prolactin adjusted for age and smoking habits (GM 193 mIU l^-1 vs. 166 mIU l^-1; p=0.047) and inhibin B adjusted for alcohol consumption (arithmetic mean (AM) 151 ng l^-1 vs. 123 ng l^-1; p=0.001) were higher in the welders compared with the referents. The whole blood Mn concentration was associated with the serum prolactin concentrations. Tobacco smoking resulted in lower serum prolactin concentrations. The GM serum prolactin concentrations of the patients did not significantly differ from that of the referents, but their AM serum inhibin B concentration was statistically significantly lower. The results may suggest an effect of Mn on the pituitary that is reversible upon cessation of exposure. Lower inhibin B concentrations in the patients could point to a functional impairment of the testicular Sertoli cells, that may be caused by a welding fume component or other factors in their work environment.     

转铁蛋白对FSH诱导卵泡颗粒细胞分化的抑制作用及其机理

转铁蛋白为一类金属结合－转运糖蛋白,经典的理论阐明其在体内的主要作用是运送铁离子到各器官与组织。根据近两年的研究,转铁蛋白除了转运铁离子的作用外,还具有局部调节卵巢功能的作用,即能抑制ＦＳＨ诱导大鼠及人卵泡颗粒细胞的功能性分化。转铁蛋白抑制ＦＳＨ衣导卵泡颗粒细胞分化的主要机理是：（１）转铁蛋白部分地抑制ＦＳＨ与卵泡颗细胞上的受体结合,减少细胞内ｃＡＭＰ生成,进而抑制了ＦＳＨ受体的维持表达。（２）转     

Conformation polymorphisms and targeted marker development

Genetic markers were developed for three targeted bovine loci using both single-stranded and double-stranded DNA conformation polymorphisms. Eight of nine DNA fragments exhibited single-stranded conformation polymorphisms while only one of nine exhibited a double-strand conformation polymorphism. All but one of the polymorphic fragments exhibited two allelic forms, with the exception being a single-stranded conformation polymorphism with three alleles. Utility of conformation polymorphisms relative to microsatellite markers for linkage map development and quantitative trait loci (QTL) mapping was assessed by comparing frequency of heterozygote parents from reference and resource families. Heterozygosity was greater for microsatellite markers (P < 0.01) and reference family parents (P < 0.01), though the disparity between marker types tended to be less dramatic for the reference family parents (P < 0.09). These results suggest conformation polymorphisms will be a useful tool for targeted marker development in linkage map and comparative map development provided genetically diverse families are studied.     

Mutational screening of SF1 and WNT4 in Tunisian women with premature ovarian failure

Background

WNT4 and SF1 genes play an important role in ovarian development. They constitute coherent candidate genes associated with premature ovarian failure (POF) pathogenesis.

Methods

We sequenced the coding region of WNT4 and SF1 in 55 Tunisian women with POF and 100 healthy controls.

Results

We identified a synonymous variation in WNT4 (c.99G>A, p.Ser33Ser) and a substitution (c.G437C) in SF1 gene inducing G146 to Ala (GGG–GCG) missense mutation. WNT4 (c.99G>A, p.Ser33Ser) was not associated with POF pathology. However, a positive association of SF1 Gly146Ala polymorphism was noted. Gly146Ala minor allele frequency was significantly higher (p = 0.029) in POF patients versus controls and Ala allele containing genotypes (p = 0.005) were positively associated with POF pathology. The carriage of 146Ala allele was also associated with a significant reduction in estradiol plasma levels.

Conclusions

SF1 Gly146Ala polymorphism seems to be associated with POF pathology in the Tunisian population likely by reducing estradiol levels.     

Prostatic inhibin peptide: Occurrence,localization and its hormonal modulation in prostates of primates and rodents

Immunocytochemical localization studies revealed the presence of 10·5 kDa inhibin in the prostatic epithelial cells of the human, non-human primates (Macaca radiata,Presbytis entellus, Callithrix jacchus), dog and laboratory rodents (guinea pigs, hamsters, rats and mice). The capability of the prostate gland to synthesize inhibinin vitro was shown by the incorporation of radiolabeled leucine into inhibin which was immuno-precipitated. Unlike most prostatic proteins, inhibin was found to be androgen-independent since no significant alteration in inhibin concentration in prostate occurred pre/post castration. Physicochemical and immunological characteristics of inhibin as revealed by high performance liquid chromatography and parallel dilution curve in a radioimmunoassay revealed similarities of inhibin in prostates of various species.