M orphological S tudies on the I nfluence of M etabolic D isturbances U pon the G onads , with S pecial R eference to the D isturbance of the TCA C ycle by KREBS *

Summary By repeated administration of fumaric acid which belongs to the K rebs 's TCA Cycle and which is influentially connected with the metabolism in body, the rabbit develops slight regressive changes in its parenchymatous organs, as well as a parenchymatous goiter. Marked atrophy is observed in the gonads especially accentuated in the testis, a correlated decrease in hyaluronidase being recognized in the atrophied testis. In this case two types are developed, i.e., hypergonadotropic hypogonadism and hyperestrogenic hypogonadism. The administration of the serum of hypergonadotropic hypogonadism to virgin rabbits results in the development of maturity of follicles with seems to be related with ovarian cystoma. Gynecomastia is observed in hyperestrogenic hypogonadism. The atrophy of testes following repeated administration of fumaric acid is inhibited by the combined administration with RNA or DNA, and with histidine. It is assumed that the fumaric acid is directly correlated with a biosynthesis of pyrimidine base. So, it is concluded that the etiological mechanism of the marked atrophy of gonads, especially the testes, is interpreted as a direct metabolic influence to the nucleic metabolism of germinal cells, and the metabolic disturbance in body influences the gonads, and the endocrine glands. The atrophy of gonads and the production of arteriosclerosis of aorta on rabbits due to the TCA Cycle disturbance seems to have given a significant value in clarifying the so‐called aging or senile symptoms.