A STUDY OF THE GLYCOGEN LEVELS OF THE RAT UTERUS AND CERTAIN SKELETAL MUSCLES DURING PREGNANCY1

Abstract

STUDIES pertaining to the hormonal control of the glycogen level of the rat uterus have shown that (a) only estrogens are effective in stimulating glycogen deposition (1-3), (b) epinephrine and posterior pituitary extracts rapidly lower uterine glycogen (4), (c) practically all the glycogen is localized in the myometrium (2, 3). This report deals with changes in uterine glycogen during the course of pregnancy, and with changes induced by epinephrine late in pregnancy. These experiments also afforded an opportunity to study glycogen changes in the “stretched” abdominal muscles and the rectus femoris of the leg. Since the primary objective was to study glycogen changes in the myometrium, the pregnant uterus, emptied of conceptus, could not be used. Rich deposits of glycogen in the remaining decidual and endometrial cells (5, 6) would mask glycogen changes in the myometrium. Consequently, the studies were made on the sterile horns of unilaterally pregnant rats.