Gonadal steroid-mediated alteration of luteinizing hormone secretion by anterior pituitary cells of young turkeys

Abstract

The magnitude of luteinizing hormone (LH) release during a 3-hr test incubation was diminished ( P < 0.05) when anterior pituitary cells from young turkeys were cultured for 24 to 120 hr. This trend was evident with basal LH release and with LH release induced by luteinizing hormone-releasing hormone (LH-RH) or hypothalamic extract. Anterior pituitary cells were cultured with various concentrations (10 −14 to 10 −6 M) of estradiol (E 2), progesterone (P 4), or testosterone (T) for 24 hr and then exposed to LH-RH or control medium for 3 hr, still in the presence of steroids. Basal LH release was potentiated ( P < 0.05) when cells were cultured with 10 −8 or 10 −6 M T, but not with E 2 or P 4. When cells were cultured with E 2, LH release in the presence of 10 −8 M LH-RH was enhanced ( P < 0.05) in a dose-dependent fashion. LH-RH mediated LH release was also enhanced ( P < 0.05) when cells were cultured with 10 −8 M P 4 or 10 −6 M T. Gonadal steroids can act directly on the anterior pituitary of the young domestic turkey to modulate LH release, with T enhancing basal LH release and E 2 potentiating LH-RH-medlated LH release.