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Title: Heterodimers and homodimers of inhibin subunits have different paracrine action in the modulation of luteinizing hormone-stimulated androgen biosynthesis

Inhibin, a gonadal hormone capable of preferential suppression of pituitary follicle-stimulating hormone (FSH) secretion, has recently been purified. The major form of this protein is an ..cap alpha beta.. heterodimer encoded by two separate genes. In contrast to the FSH-suppressing action of the ..cap alpha beta.. heterodimer, the ..beta beta.. homodimer stimulates FSH secretion. Luteinizing hormone (LH)-secreting pituitary cells and gonadal androgen-producing cells have long been shown to form a closed-loop feedback axis. Based on recent studies demonstrated the FSH stimulation of inhibin biosynthesis by ovarian granulosa and testis Sertoli cells, an additional closed-loop feedback axis exists between pituitary FSH- and gonadal inhibin-producing cells. Because uncharacterized Sertoli cell factors have been suggested to either stimulate or inhibit androgen production by testicular Leydig cells, the authors have tested the intragonadal paracrine actions of heterodimers and homodimers of inhibin subunits. In primary cultures of testis cells, the ..cap alpha beta.. heterodimer of inhibin enhances Leydig cell androgen biosynthesis stimulated by LH, whereas the ..beta beta.. homodimer suppresses androgen production. The data indicate that the inhibin-related gene products synthesized by Sertoli and granulosa cells may form heterodimers or homodimers to serve as intragonadal paracrine signals in the modulation of LH-stimulated androgen biosynthesis andmore » allow cross-communication between the two feedback loops.« less
Authors:
; ; ; ; ; ;
Publication Date:
OSTI Identifier:
5237117
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States); Journal Volume: 84:14
Research Org:
Univ. of California, San Diego, CA (USA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ANDROGENS; BIOSYNTHESIS; RADIOIMMUNOASSAY; GONADOTROPINS; PHARMACOLOGY; FSH; LH; LIQUID COLUMN CHROMATOGRAPHY; OVARIES; RATS; TESTES; ANDROSTANES; ANIMALS; BODY; CHROMATOGRAPHY; FEMALE GENITALS; GONADS; HORMONES; IMMUNOASSAY; IMMUNOLOGY; ISOTOPE APPLICATIONS; MALE GENITALS; MAMMALS; ORGANIC COMPOUNDS; ORGANS; PEPTIDE HORMONES; PITUITARY HORMONES; RADIOASSAY; RADIOIMMUNOLOGY; RODENTS; SEPARATION PROCESSES; STEROID HORMONES; STEROIDS; SYNTHESIS; TRACER TECHNIQUES; VERTEBRATES 550601* -- Medicine-- Unsealed Radionuclides in Diagnostics