Feedback effects of growth hormone on anterior pituitary function in chickens.
Circulating GH concentrations were suppressed 24 h after intracerebroventricular (i.c.v.) injection of native or recombinant DNA-derived chicken GH (rcGH) (10 micrograms in 4 microliters vehicle) into the right lateral ventricles of conscious 6-week-old cockerels. Plasma concentrations of LH were suppressed within 1 h of i.c.v. administration of GH at doses of 1 or 10 micrograms, and remained suppressed for 24 h in birds injected with the highest concentration of GH. In contrast, concentrations of plasma prolactin were increased 24 h after i.c.v. administration of GH (10 micrograms). The i.v. administration of rcGH (at concentrations of 10 or 100 micrograms/kg) did not mimic the effects of i.c.v. injection of GH. These results demonstrate central effects of GH on pituitary function in the domestic fowl.
Lea
R W
RW
Department of Physiology, University of Alberta, Edmonton, Canada.
Harvey
S
S
D000818:Animals; D002645:Chickens / Q000502:physiology*; D005246:Feedback; D013006:Growth Hormone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects* / Q000502:physiology; D011388:Prolactin / Q000097:blood
D011388:Prolactin; D007986:Luteinizing Hormone; D013006:Growth Hormone