THE INFLUENCE OF PITUITARY GONADOTROPHIN AND OF MIXTURES OF PITUITARY AND CHORIONIC GONADOTROPHIN ON THE FOLLICLES IN THE OVARY OF THE HYPOPHYSECTOMIZED RAT AND THE NORMAL MOUSE

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Abstract
The influence of gonadotrophic hormones on the ovary was studied in young mice and young hypophysectomized rats. One ovary was removed before and the other at the end of treatment. All follicles and corpora lutea were measured and the distr. according to size detd. In normal mice, pituitary extract induced the formation of corpora lutea and increased the total number of follicles and corpora lutea by 55%. Addition of chorionic gonadotrophin to the extract raised this increase to 93% but this additional increase was limited to the follicles with a diameter up to ca. 110u. The number of corpora lutea produced during the joint admn. of pituitary and chorionic gonadotrophin was larger than the number produced by pituitary extract alone (65 vs. 39). They were larger on the avg. (although never exceeding the largest follicles) and showed less tendency to atrophy. The addition of chorionic gonadotrophin was shown to be followed by an acceleration of the growth rate of medium-sized follicles. Similar results were obtained in hypophysectomized rats; however, these were less conclusive than those obtained in mice because of a high mortality among controls and development of resistance to chorionic gonadotrophin. The % of cavity-containing follicles was in no case increased by the treatment. Atresia showed no conspicuous change. In normal mice, removal of 1 of the ovaries always led to a slight increase in the number of follicles in the remaining ovary, nearly all size-groups contributing to this increase.