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 and allow cross-communication between the two feedback loops.
- Research Organization:
- Univ. of California, San Diego, CA (USA)
- OSTI ID:
- 5237117
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 84:14
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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