Lb. Dain et al., EVIDENCE FOR THE PRODUCTION OF A GROWTH-INHIBITORY FACTOR BY HUMAN GRANULOSA-LUTEAL CELLS, Molecular reproduction and development, 36(2), 1993, pp. 159-163
The factors involved in the inhibition of ovarian follicular cellular
growth after the luteinizing hormone (LH) surge are poorly established
. The aim of this study was to investigate the production of an inhibi
tory growth factor by human ovarian cells. Luteinized granulosa cells
were obtained from an assisted fertilization program and were cultured
in the presence or absence of follicle-stimulating hormone (FSH) and
estradiol. Data obtained by cell counting showed that the number of hu
man luteinized granulosa cells cultured in the presence of fetal bovin
e serum (10%) increased 1.8-fold within a 2-day period. In serum-free
medium, human luteinized granulosa cells were able to incorporate H-3-
thymidine, measured during consecutive 48 h periods. During all the pe
riods tested (up to 7 days), low basal levels of thymidine incorporati
on were measured and were further reduced in the presence of FSH (200
ng/ml) and estradiol (500 ng/ml). To elucidate the possible production
of an inhibitory growth factor, H-3-thymidine incorporation by rat gr
anulosa cell cultures was measured in the presence of conditioned medi
a (CM; from human granulosa cell cultures). In this system, FSH and es
tradiol elicited a tenfold increase in thymidine incorporation. The ad
dition of CM (10% v/v collected on day 2) to FSH- and estradiol-treate
d granulosa cell cultures produced an inhibition (61%) of thymidine in
corporation. The active factor in CM withstood freeze-thawing, was sta
ble for several weeks at -20-degrees-C, became unstable at 4-degrees-C
, and was heat labile and sensitive to proteolysis. Ultrafiltration us
ing membranes with different molecular weight cutoffs suggested that t
he factor had a molecular weight >30,000 dalton. We suggest that an in
hibitory growth factor produced by human luteinized granulosa cells co
uld be involved in the differentiation of growing follicles to corpus
luteum. (C) 1993 Wiley-Liss, Inc.