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Tag: Follistatin

Activin Modulates Differential Effects of Estradiol on Synthesis and Secretion: DISCUSSION(3)

The question arises whether the effect of estradiol on FSHp gene expression, which was very dramatic (up to 70%), may be mediated by the relatively lesser decrease (<46%) in expression of activin. We hypothesize that a small reduction in free Read More

Activin Modulates Differential Effects of Estradiol on Synthesis and Secretion: DISCUSSION(2)

The data reported herein confirm that during anestrus, estradiol can regulate secretion of gonadotropins by a direct action on the anterior pituitary gland in the absence of any hypothalamic factors. These effects of estradiol appear to be mediated, at least Read More

Activin Modulates Differential Effects of Estradiol on Synthesis and Secretion: DISCUSSION(1)

Current concepts of regulation of gonadotrope function include the autocrine-paracrine regulation of FSH synthesis and secretion by activin and follistatin. Some reports have documented small but significant increases in mRNAs for activin pB and inhibin a after gonadectomy in rats. Read More

Activin Modulates Differential Effects of Estradiol on Synthesis and Secretion: RESULTS

FSH and LH Release from Pituitary Cells after Estradiol Treatment Estradiol reduced secretion of FSH in a dose-dependent manner (P < 0.001; Fig. 1A). In the presence of 0.01 and 1.0 nM estradiol, FSH concentrations were suppressed by 37% and Read More

Activin Modulates Differential Effects of Estradiol on Synthesis and Secretion: MATERIALS AND METHODS(3)

Slot Blot Analysis To corroborate the RT-PCR results, steady state amounts of FSHp mRNA were also measured by slot blot analysis as previously described. Amounts of mRNA for activin pB and follistatin were insufficient for detection by this method. Polyadenylated Read More

Activin Modulates Differential Effects of Estradiol on Synthesis and Secretion: MATERIALS AND METHODS(2)

Treatments Estradiol (0.01 or 1.0 nM) was added to the cells for the final 24 h of culture. After treatment, medium was collected from all cultures and stored at -20°C until hormone assays were performed. To immunoneutralize activin, monoclonal antibody Read More

Activin Modulates Differential Effects of Estradiol on Synthesis and Secretion: MATERIALS AND METHODS(1)

Animals and Experimental Design Five sexually mature, western-range ewes were used during the anestrous season (June) in Colorado. Anestrous status was confirmed by the absence of ovarian activity at slaughter. Anterior pituitary glands were collected following anesthesia with sodium pentobarbital Read More

Activin Modulates Differential Effects of Estradiol on Synthesis and Secretion: INTRODUCTION(2)

Maintenance of normal reproductive function is dependent on the precise regulation of gonadotropin biosynthesis and secretion. Control of gene expression for the p subunit of both gonadotropins is regulated by circulating gonadal steroids as well as by hypothalamic factors, principally Read More

Activin Modulates Differential Effects of Estradiol on Synthesis and Secretion: INTRODUCTION(1)

Reproductive activity of sheep varies with season. Female sheep in temperate latitudes become anestrus during late winter or early spring and resume reproductive activity in late summer or early fall. Seasonal fluctuation in reproductive activity is most likely due to Read More

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