title: Studies on low molecular weight follicle stimulating hormone receptor binding inhibitor (FSH-RBI) from ovine testis.
abstract: Follicle stimulating hormone receptor binding inhibitor (FSH-RBI) has been isolated from the aqueous extracts of ovine testis using Sephadex column chromatography. Sephadex G-75 fraction IV was found to inhibit the binding of (125I) FSH to rat testis receptors. Further purification of Sephadex G-75 fraction on Sephadex G-25 column gave three fractions (I-III). The maximum inhibitory activity to inhibit (125I) FSH binding to rat testis receptor was associated with fraction III only. FSH-RBI exerted a greater inhibitory effect on the formation of the hormone-receptor complex rather than on the dissociation of the preformed complex. FSH-RBI did not inhibit the binding of (125I) LH to rat testis receptors. A significant decrease in the mouse ovarian weight was observed when FSH-RBI was injected to hCG-primed female mice. The molecular weight determination studies show that molecular weight of FSH-RBI is approximately 1400 Daltons.
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D005640:Follicle Stimulating Hormone / Q000037:antagonists & inhibitors* / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D006727:Hormone Antagonists / Q000302:isolation & purification / Q000494:pharmacology*; D007265:Inhibins; D008297:Male; D008970:Molecular Weight; D051381:Rats; D011962:Receptors, FSH / Q000187:drug effects / Q000378:metabolism*; D012756:Sheep; D013737:Testis / Q000032:analysis*
chemical_list: D006727:Hormone Antagonists; D011962:Receptors, FSH; D007265:Inhibins; D005640:Follicle Stimulating Hormone