Human Reproduction, Vol 12, 2735-2740, Copyright © 1997 by Oxford University Press
CA Alouf, LE Reichert Jr, TA Kellom and DW Lee
We previously reported that human follicular fluid contained a protein that
inhibits binding of 125I-human FSH to its membrane receptor (FSH- BI) and
demonstrates FSH-like agonist activity in vitro. The cellular origin of
FSH-BI was unknown, although ovarian granulosa cells seemed a likely
source. To address this question, human granulosa cells were collected from
patients during routine in-vitro fertilization (IVF) or gamete
intra-Fallopian transfer (GIFT) procedures. Cells from 98 patients were
cultured and then examined for their ability to secrete FSH
receptor-binding inhibitory activity into the culture medium. The function
of the cultured cells was confirmed by their ability to respond to added
FSH with conversion of exogenous androstenedione to oestradiol.
Radioreceptor assays were performed individually on cell culture medium
obtained from granulosa cell cultures from these 98 patients. Cultured
granulosa cells, under basal conditions (in the absence of FSH
stimulation), secreted significant FSH-BI activity into the culture medium.
In order to accumulate enough material for further study, this culture
medium was pooled and lyophilized. The lyophilized medium retained FSH-BI
activity, and also demonstrated FSH agonist activity by stimulating
oestradiol synthesis in cultured rat Sertoli cells. A fraction showing a
single component after purification by polyacrylamide gel electrophoresis
had an estimated molecular weight of 25000, and inhibited 125I-human FSH
binding to receptor by 50% at 2.5 microg/ml. The results indicate that
human granulosa cells secrete a protein with FSH-like activity having
potential significance as a local regulator of FSH action in the ovary.
ARTICLES
Cultured human granulosa cells secrete a follicle stimulating hormone receptor-binding inhibitor
Department of Anatomy, Cell Biology and Neurobiology, Albany Medical College, NY 12208, USA.
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