Steroids modulate the release of luteinizing hormone from quail pituitary cells

An enzymatically dispersed pituitary preparation from male Japanese quail (Coturnix coturnix) was used to study the effects of gonadal and adrenal steroids on gonadotropin release. Cells were preincubated for 18 hr with or without steroids and then challenged with chicken luteinizing hormone-releasing hormone (cLH-RH I; Gln8-LH-RH). Preincubation with testosterone (T; 10 nM) significantly suppressed (P less than 0.05) luteinizing hormone release in response to cLH-RH I (10 ng/ml). Preincubation with 5 alpha-dihydrotestosterone (5 alpha-DHT) (10 nM) caused even further suppression of LH-RH-stimulated LH release while the same concentration of 5 beta-dihydrotestosterone and estradiol-17 beta had no effect. In addition, preincubation with corticosterone (10 nM) significantly (P less than 0.01) suppressed the amount of LH released in response to cLH-RH I. Pituitary cells from immature males, when stimulated with cLH-RH I, released LH in a dose-related manner. Neither T nor 5 alpha-DHT (10 nM) altered the effect of LH-RH. These data suggest that T and 5 alpha-DHT play a role in mediating LH release in the avian pituitary while 5 beta-reduced androgens have no effect. There appears to be no androgen effect in the immature quail. In addition, corticosterone seems to be a factor in controlling gonadotropin secretion in the quail.