Ovarian aromatase activity in scorbutic mutant rats unable to synthesize ascorbic acid

Osteogenic disorder syndrome rats are unable to synthesize ascorbic acid owing to the lack of l-gulonolactone oxidase, and become scorbutic within a few weeks without the supply of ascorbic acid. We studied effects of ascorbic acid deficiency on the ovarian aromatase activity in vivo using osteogenic disorder syndrome rats. The ovarian aromatase activity in ascorbic acid-deficient osteogenic disorder syndrome rats was significantly higher than that in normal or ascorbic acid-supplied osteogenic disorder syndrome rats. The activity in hypophysectomized immature rats was extremely low, but increased after treatment with pregnant mare serum gonadotropin, regardless of the presence or absence of ascorbic acid. The extent of the increase was the same among experimental groups. The present results indicate that ascorbic acid at physiological level lowers the ovarian aromatase activity, whereas it does not impair the responsiveness of the aromatase activity to gonadotropins.