Inhibin: From Concept to Reality

Inhibin production by bovine ovarian tissues in vitro and its regulation by androgens

“…It is possible, however, that the concentrating effect of ultrafiltration promotes aggregation of lower molecular weight forms. The loss of inhibin activity of bovine granulosa cell culture medium by heating to 80°C for 30 min is consistent with the finding that inhibin present in Sertoli cell culture medium (Steinberger & Steinberger, 1976) and rete testis fluid (Franchimont et al, 1979) is also thermolabile.…”

“…The assigned molecular weight of inhibin is usually between 10 000 and 30 000 although inhibin activity has been reported in molecular weight fractions of > 100 000 and < 5000 (Franchimont et al, 1979;de Jong, Jansen & van der Molen, 1981). This inconsistency is probably due to (1) the different methods of measuring inhibin activity and determining molecular weight, (2) the fact that few of the studies have been performed with purified inhibin, and (3) because inhibin appears to be biochemically heterogeneous (Franchimont et al, 1979).…”

“…This inconsistency is probably due to (1) the different methods of measuring inhibin activity and determining molecular weight, (2) the fact that few of the studies have been performed with purified inhibin, and (3) because inhibin appears to be biochemically heterogeneous (Franchimont et al, 1979). The inhibin activity of bovine granulosa cell culture medium after ultrafiltration was only found in the Mr > 100 000 fraction.…”

“…There is increasing evidence to indicate that inhibin produced by the ovary is physiologically important in the regulation of pituitary FSH secretion, and consequently follicular development (Franchimont et al, 1979. Follicular granulosa cells secrete inhibin in vitro (Erickson & Hsueh, 1978;Anderson & de Paolo, 1981; and are therefore considered to be the site of ovarian inhibin production.…”

Increase in ovulation rate after immunization of Merino ewes with a fraction of bovine follicular fluid containing inhibin activity

“…Inhibin, as defined by its capacity in various species to suppress plasma follicle-stimulating hormone (FSH) specifically with little or no effect on plasma luteinizing hormone (LH) concen¬ trations (Davies, Main & Setchell, 1978;de Jong, 1979;Franchimont et al, 1979;Channing, Anderson, Hoover, Gagliano & Hodgen, 1981;Cummins, O'Shea, Bindon, Lee & Findlay, 1983), is a component of ovarian feedback on pituitary function. It might therefore be expected to play a role in the regulation of ovulation rate.…”