Glucose-6-phosphate Dehydrogenase Activity in the Goat Ovary

The distribution and activity of nicotinamide-adenine dinucleotide phosphate (NADP)-dependent glucose-6-phosphate dehydrogenase (G-6-PDH) in the goat ovary were examined histochemically. Tokara goats on Day 5 of the estrous cycle and on Day 5 of the pregnancy were used. The G-6-PDH activity was determined by the slightly modified method of NACHLAS et al. Both the nonpregnant goat ovary and the early pregnant goat ovary showed a similar distribution and activity of this enzyme. In the normal preantral follicles, the granulosa cells exhibited moderate enzyme activity and the theca cells very weak. In the normal antral follicles, enzyme activity was strong in the granulosa cells, and was very strong in the theca interns but weak in the theca externa. The corpora lutes showed a very strong enzyme activity. These histochemical observations suggest that the granulosa cells and theca interns of the normal antral follicles and the corpora lutea in the goat ovary are likely to contribute to steroidogenesis. A weak or very weak enzyme activity in atretic follicles, ovarian stroma and germinal epithelium suggests that they are not active in steroidogenesis.