Gonadal steroids and anterior lobe dynorphin in the male rat.
Immunoreactive (ir)-dynorphin levels were measured, and the species characterized by high performance liquid chromatography (HPLC), in the pituitary and hypothalamus of intact and castrate male rats. On HPLC, ir-dynorphin co-eluted with authentic dynorphin A 1-8, dynorphin A 1-17 and dynorphin 1-32 in the hypothalamus and intermediate lobe; in two different reversed phase (RP)-HPLC systems, anterior lobe ir-dynorphin co-eluted uniquely with dynorphin 32 (4K dynorphin). Anterior lobe levels of total ir-dynorphin were significantly lowered 7 days after castration, while HPLC profiles in all tissues remained unchanged. The change in anterior pituitary ir-dynorphin levels was reversed in a dose-related manner by dihydrotestosterone (15-500 micrograms/100 g b. wt/day); estradiol benzoate (3 micrograms/100 g/day) was without effect. The changes on castration and androgen administration suggest that gonadal steroids play a role in the regulation of dynorphin, as well as gonadotrophins and prolactin, within the anterior pituitary gland.
Fullerton
M J
MJ
Medical Research Centre, Prince Henry's Hospital, Melbourne, Australia.
Smith
A I
AI
Clements
J A
JA
Funder
J W
JW
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D013196:Dihydrotestosterone / Q000494:pharmacology; D004399:Dynorphins / Q000032:analysis*; D007028:Hypothalamic Hormones / Q000032:analysis; D007031:Hypothalamus / Q000032:analysis*; D008297:Male; D009919:Orchiectomy; D010446:Peptide Fragments / Q000032:analysis; D010902:Pituitary Gland / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains
D007028:Hypothalamic Hormones; D010446:Peptide Fragments; D013196:Dihydrotestosterone; D004399:Dynorphins; C026770:dynorphin (1-8)