AJP - Endocrinology and Metabolism, Vol 263, Issue 5 E943-E949, Copyright © 1992 by American Physiological Society
Oxoanions stimulate in vitro ovulation and signal transduction pathways in goldfish (Carassius auratus) follicles
S. Y. Hsu and F. W. Goetz
Department of Biological Sciences, University of Notre Dame, Indiana 46556.
The present study investigated the effects of a number of oxoanion
compounds on in vitro ovulation of goldfish follicles and ovarian second
messenger activities. Significant levels of ovulation were induced by 0.1
mM sodium chromate, 0.1 mM sodium metavanadate, 10 mM sodium molybdate, 0.1
mM sodium orthovanadate, 5 mM sodium selenate, 0.5 mM sodium tungstate, and
0.1 mM vanadyl sulfate. At levels that significantly stimulated ovulation,
metavanadate, molybdate, orthovanadate, tungstate, and vanadyl sulfate also
stimulated follicular phosphatidylinositol cycling and inhibited ovarian
alkaline phosphatase activity. Moreover, the ovulation induced by these
oxoanions was not inhibited by indomethacin (10 micrograms/ml), while
ovulation induced by selenate and chromate was. In contrast, only
vanadium-containing compounds significantly stimulated prostaglandin (PG)
synthesis, and, in fact, selenate significantly inhibited PG production.
Finally, only sodium molybdate- and vanadium-containing compounds appeared
to increase follicular adenosine 3',5'-cyclic monophosphate content. While
all oxoanions stimulated in vitro ovulation, they had differential effects
on certain signal transduction pathways when tested at concentrations that
stimulated in vitro ovulation. From the results, two basic groups could be
delineated, one containing tungstate-, molybdate-, and vanadium-containing
compounds and the other selenate and chromate. Thus the mechanism by which
ovulation is induced by chromate and selenate may be different from that of
vanadium-containing compounds, molybdate, and tungstate.(ABSTRACT TRUNCATED
AT 250 WORDS)
