Gonadal steroids and anterior lobe dynorphin in the male rat

Meryl J. Fullerton, A. Ian Smith, Judith A. Clements, John W. Funder

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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 μg/100 g b. wt/day); estradiol benzoate (3 μg/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.

Original languageEnglish
Pages (from-to)303-308
Number of pages6
JournalJournal of Steroid Biochemistry
Issue number2
Publication statusPublished - 1 Jan 1989
Externally publishedYes

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