Gonadotropic control of secretion of dimeric inhibins and activin A by human granulosa-luteal cells in vitro.
OBJECTIVE
It is well established that human granulosa cells and luteal cells express inhibin/activin subunit protein and secrete immunoreactive inhibin. The gonadotropic control of secretion of different molecular forms of inhibin and activin A by granulosa-luteal cells (G-LCs) was investigated using recently developed specific enzyme immunoassays (EIAs).


METHODS
Granulosa-luteal cells obtained at IVF egg pickup were cultured in a serum-free medium at 37 degrees C in a water-saturated incubator with 5% CO2 for up to 5 days. Experiments with varying concentrations of human FSH, hLH, and hCG were carried out.


RESULTS
FSH raised the secretion of inhibin A and pro-alpha C-containing inhibins after 24 and 48 hr in culture. Inhibin B was raised after 24 hr and activin A was raised after 48 hr of FSH treatment. LH treatment for 24 hr stimulated inhibin A, inhibin B, pro-alpha C, and activin A. hCG stimulated G-LC secretion of inhibin A after 48 hr and pro-alpha C after 24 hr. Paradoxically, inhibin B secretion was inhibited by 1 and 10 ng/ml hCG after 48 hr. Activin A was stimulated by hCG after 24 and 48 hr of incubation. G-LC secretion of estradiol and progesterone was also stimulated significantly by LH and hCG.


CONCLUSIONS
Secretion of dimeric inhibins and activin A is controlled differentially by gonadotropins.
Muttukrishna
S
S
Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Headington, UK.
Groome
N
N
Ledger
W
W
D028341:Activins; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000096:biosynthesis; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000032:analysis / Q000187:drug effects; D006062:Gonadotropins / Q000502:physiology*; D006107:Granulosa Cells / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D007265:Inhibins / Q000378:metabolism*; D008184:Luteal Cells / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000187:drug effects; D011374:Progesterone / Q000096:biosynthesis; D013997:Time Factors
D006062:Gonadotropins; D028341:Activins; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D004958:Estradiol; D007265:Inhibins; D007986:Luteinizing Hormone