AJP - Endocrinology and Metabolism, Vol 240, Issue 2 209-E215, Copyright © 1981 by American Physiological Society
Specific FSH suppression in male rat by porcine follicular fluid
J. R. Lorenzen, G. H. Dworkin and N. B. Schwartz
A variety of protocols using intact, castrated, and sham-castrated adult
male rats was used to test the ability of porcine follicular fluid to
selectively suppress serum follicle-stimulating hormone (FSH). A total dose
of 500 microliters follicular fluid injected intraperitoneally will
suppress FSH in the rat with testes within 5 h of injection. This is more
than is necessary to suppress FSH in the intact or ovariectomized female. A
total dose of 1 ml of follicular fluid is needed to suppress FSH reliably
in the castrated male rat. Serum FSH is suppressed significantly beginning
between 4 and 5.5 h after intraperitoneal injection of 1 ml of follicular
fluid and 3 h after intravenous injection. The suppression continues until
10 h postinjection and is abated by 26 h postinjection. Serum luteinizing
hormone (LH) is unaffected by follicular fluid in any protocol tested. It
is concluded that 1) follicular fluid can suppress serum FSH in the male
if large enough doses are given, 2) follicular fluid has no effect on serum
LH, and 3) follicular fluid suppresses serum FSH levels in the male as well
as previously tried testicular sources. These results suggest that the
delay in demonstrating the existence of inhibin may be due to the use of
males as both source and test subject.
