In Vitro Changes in Secretion Activity of Rat Ovarian Fragments Induced by Molybdenum

The aim of this in vitro study was to examine the secretion activity (progesterone, 17 beta-estradiol and insulin-like growth factor-I) of rat ovarian fragments after molybdenum (Mo) addition. Rat ovarian fragments were incubated with ammonium molybdate (NH4)(6)Mo7O24 center dot 4H(2)O at the doses 90, 170, 330 and 500 mu g.ml(-1) for 24 h and compared with control group without Mo addition. Release of progesterone (P-4), estradiol (17 beta-estradiol) and insulin-like growth factor I (IGF-I) by ovarian fragments was assessed by radioimmunoassay (RIA). Data show that P-4 release by ovarian fragments was not affected by (NH4)(6)center dot Mo7O24 center dot 4H(2)O addition at all the doses used (90-500 mu g.ml(-1)). However, addition of ammonium molybdate was found to cause a significant (P<0.05) dose-dependent decrease (at the doses 90, 170 and 500 mu g.ml(-1)) in release of 17 beta-estradiol by ovarian fragments in comparison to control. Also, addition of ammonium molybdate significantly (P<0.05) inhibited IGF-I release at all the doses (90-500 mu g.ml(-1)) used in the study. Results suggest ammonium molybdate induced inhibition in the release of growth factor IGF-I and its dosedependent effect on secretion of steroid hormone 17 beta-estradiol but not progesterone. These data contribute to new insights regarding the mechanism of action of Mo on rat ovarian functions.