Type beta transforming growth factor (TGF-beta) is a potent stimulator of the basal secretion of follicle stimulating hormone (FSH) in a pituitary monolayer system.
In view of striking similarities between TGF-beta and inhibin, we investigated the possibility that TGF-beta might modulate pituitary hormone release in vitro. Long term incubations of beta transforming growth factor (TGF-beta) with rat anterior pituitary cells for 48 hr stimulates the basal secretion of FSH in a dose-dependent manner. The secretion of LH, TSH, GH, ACTH and PRL is not modified by TGF-beta. The minimal effective concentration of TGF-beta is 10 pg/ml (less than 500 attomolar) and is dose dependent over a range from 1 pg to 10 ng/ml. Treatment of cells with TGF-beta for short incubation times (4 hr) in assays similar to that used for hypophysial releasing factors is not effective, indicating that TGF-beta acts through a cellular mechanism distinct from that of LRF. Inhibin-A, recently characterized on the basis of its capacity to specifically inhibit the secretion of FSH in the 48 hr bioassay system inhibits the stimulatory effect of TGF-beta on FSH-release. Analyses of the dose response curves indicate that the interaction occurs in a typical non-competitive manner. The results suggest that a TGF-beta-like molecule, present in follicular fluid, may be responsible for the FSH-releasing activity ("anti-inhibin" activity) observed by us and others during the process of isolating inhibin from follicular fluids. They also suggest an important role for inhibin and the TGF-beta related molecules in modulating pituitary gonadotropin release.
Ying
S Y
SY
Becker
A
A
Baird
A
A
Ling
N
N
Ueno
N
N
Esch
F
F
Guillemin
R
R
D000818:Animals; D002478:Cells, Cultured; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D006133:Growth Substances / Q000494:pharmacology*; D066298:In Vitro Techniques; D007265:Inhibins / Q000494:pharmacology; D006080:Ovarian Follicle / Q000502:physiology; D010455:Peptides / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D051381:Rats; D012636:Secretory Rate / Q000187:drug effects; D013268:Stimulation, Chemical; D015291:Transforming Growth Factors
D006133:Growth Substances; D010455:Peptides; D007265:Inhibins; D015291:Transforming Growth Factors; D005640:Follicle Stimulating Hormone