Novel ovarian regulatory peptides: inhibin, activin, and follistatin.
Based on the extensive amount of research on inhibin and related polypeptides accomplished during the past 5 years, the inhibin concept put forth more than 50 years ago has not only become well established but also more complex than originally imagined. The closed-loop feedback mechanism of ovarian inhibin and pituitary FSH has been joined by possible "inhibin-like" actions of follistatin and FSH-stimulatory effects of activin. In addition, in vitro experiments suggest possible autocrine and paracrine functions for the gonadal polypeptide hormones. Figure 3 shows a simplistic diagram summarizing our current understanding of inhibin/activin and follistatin action along the hypothalamic-pituitary-gonadal axis. Hopefully, research in the coming years will allow us to remove the many question marks still remaining but will undoubtedly add others.
Ling
N
N
Department of Molecular Endocrinology, Whittier Institute for Diabetes and Endocrinology, La Jolla, CA 92037.
DePaolo
L V
LV
Bicsak
T A
TA
Shimasaki
S
S
D028341:Activins; D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D038681:Follistatin; D006023:Glycoproteins / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology; D006801:Humans; D007265:Inhibins / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology; D008969:Molecular Sequence Data; D010053:Ovary / Q000737:chemistry*
D038681:Follistatin; D006023:Glycoproteins; D028341:Activins; D007265:Inhibins; D005640:Follicle Stimulating Hormone