Changes in catalase activity during follicular growth, atresia and luteinization in rat ovary.

Quantitative changes have been observed in the catalase activity during follicular growth, induced atresia and in corpora lutea of cycle and pregnancy. Large growing and preovulatory follicles showed higher enzyme activity as compared to the smaller follicles; the activity was mainly present in the thecal layer of the preovulatory follicle. After the blockade of ovulation with barbiturate, the activity increases significantly in the whole follicle and also in the thecal layers till third day of ovulation and afterward it declines on 5th day, suggesting that rise in catalase activity may exert a protective function against lytic actions of peroxide which is known to be produced in the ovary during several metabolic and steroidogenic events. The corpora lutea of the cycle showed significantly less enzyme activity than the corpora lutea of pregnancy. The significance of catalase activity during follicular and corpus luteum degeneration is discussed.

Cholinesterase activity in the corpus luteum of the sheep and pig.

The acetylcholinesterase (AHhE) activity in the corpora lutea of ovaries from sheep has been examined at different stages of pregnancy and the oestrous cycle, by both quantitative and histochemical techniques. The enzyme activity rose during the early part of pregnancy and then levelled out; it appeared to fall sharply at term. During the oestrous cycle the AChE activity was much lower but showed time-related changes. A few results from pigs and cows are included. The cows corpora lutea, unlike those of the sheep and pig contained butyrylcholinesterase (BuChE) as well as AChE. The results are discussed in terms of the possible function of non-neuronal cholinesterases.