Purification and chemical composition of a low molecular weight follicle-stimulating hormone binding inhibitor from porcine follicular fluid.
Porcine follicular fluid contains several factors capable of inhibiting the binding, in vitro, of follicle-stimulating hormone (FSH) to receptor, including an agonist and an antagonist of FSH biological activity in vitro. FSH receptor-binding inhibitory activity (FSH-BI) was determined with assays using radioligand (125iodide-human FSH) receptor (calf-testes membrane); in vitro biological assays (cultured immature rat Sertoli cells) were used to determine antagonist/agonist activity. FSH antagonist activity is due to a low (less than 5000) molecular weight FSH-BI that is soluble in acidic acetone and insoluble in diethyl ether allowing preparative scale isolation. Additional purification was achieved by anion-exchange and reverse-phase high-performance liquid chromatography. Highly purified, biologically active FSH-BI contained the amino acids Ser, Gly, Arg, Thr, Ala, Pro, Val, and Lys; hexoses (phenol-sulfuric acid-positive reaction); and ethanolamine. Thus, this FSH antagonist appears to be a complex glycopeptide--possibly derived from membrane components, as suggested by the presence of ethanolamine and carbohydrate residues. Porcine follicular fluid, therefore, contains a low molecular weight FSH antagonist that, along with the high molecular weight FSH agonist previously identified, may regulate gonadal responsiveness to FSH through interactions with the FSH receptor.
Sluss
P M
PM
Department of Urology, University of Rochester, School of Medicine and Dentistry, New York 14642.
Schneyer
A L
AL
Andersen
T T
TT
Reichert
L E
LE
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D002352:Carrier Proteins; D002851:Chromatography, High Pressure Liquid; D004983:Ethanolamines / Q000032:analysis; D005260:Female; D005640:Follicle Stimulating Hormone / Q000037:antagonists & inhibitors; D015571:Follicular Fluid / Q000032:analysis*; D006020:Glycopeptides / Q000032:analysis / Q000302:isolation & purification*; D008970:Molecular Weight
D000596:Amino Acids; D002241:Carbohydrates; D002352:Carrier Proteins; D004983:Ethanolamines; C484018:FSH-BI protein, human; D006020:Glycopeptides; D005640:Follicle Stimulating Hormone