STUDIES ON THE MECHANISM OF NIDATION. XVII. HISTOCHEMICAL ANALYSIS OF DECIDUALIZATION IN THE RAT

Abstract

Histochemical changes in the activities of acid phosphatase, considered to be characteristic of lysosomes, and of alkaline and adenosinetriphosphatase, were studied during the period of regression of deciduomata in the uterus of the pseudopregnant rat. The activity of alkaline phosphatase and adenosinetriphosphatase declined rapidly prior to and during the period of involution. A rise in the activity of acid phosphatase began antime-sometrially at the periphery of the deciduomata, before shrinkage was evident in the histological preparations. Acid phosphatase activity remained high during the period of regression and subsequently declined. Enzymatic activity was also high in the metrial gland cells, and in the macrophages which appeared in the uterus and apparently contributed to the breakdown and removal of the deciduomata. Changes were also demonstrated in the amount of free lipids and connective tissue components of the uterus. Great variability was noted in the appearance of uteri from animals killed at the same time intervals following stimulation during the period of regression of deciduomata and this variability was related to the time of occurrence of the 1st ovulation terminating the period of pseudopregnancy in deciduomata bearing rats.