The total and specific activity of 3 beta-hydroxy-delta 5-steroid dehydrogenase, isocitrate dehydrogenase (NADP+) and glucose-6-phosphate dehydrogenase were measured in ovarian follicles from the domestic fowl. The enzymes were assayed in the five largest yolk-filled follicles which were sampled twice during the ovulatory cycle, at 1 h and 16 h before an expected ovulation. The total and specific activity of granulosa enzymes increased throughout the hierarchy and reached a maximum in the largest follicle. The relative increase in 3 beta-hydroxy-delta 5-steroid dehydrogenase activity was greater than that of the other two enzymes examined. The total thecal 3 beta-hydroxy-delta 5-steroid dehydrogenase activity reached a maximum in the third and fourth largest follicles. Thereafter its activity decreased up to the time of ovulation. The activity of 3 beta-hydroxy-delta 5-steroid dehydrogenase and glucose-6-phosphate dehydrogenase in follicles collected 1 h before and ovulation were significantly less than the activity in corresponding follicles collected 16 h before an ovulation.
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DM Armstrong (1982) studied this question.