GLYCOGEN IN THE DECIDUAL TISSUE OF THE RAT UTERUS

Abstract

SUMMARY: Glycogen was investigated in uteri of intact and progesterone-treated spayed rats with and without deciduomata. Samples of whole uterus, endometrium and myometrium were analysed. With development of deciduoma in intact animals the glycogen concentration of whole uterus increased from 68 to 125 mg./100 g. wet weight. There was no change in the myometrial glycogen concentration; i.e. 74 mg./100 g. without deciduoma and 73 mg./100 g. wet weight in the decidual myometrium. The endometrial glycogen content of decidual tissue was 221 mg./100 g. wet weight. Since myometrial glycogen was constant, the increases observed in the decidual tissue of whole uteri must be due to an increase in the amount of endometrium and/or an increase in the concentration of glycogen in the endometrium. As the deciduoma developed the proportion of endometrium increased from 9% in the uninjured horn to 34% in the injured horn. Thus, an increase in the amount of endometrium contributes to the increase in the glycogen concentration. Similar changes were observed in whole uterus, myometrium and endometrium of the spayed animals treated with progesterone. Previous work on uterine glycogen in rats indicated that oestrogens cause glycogen deposition and this occurs only in the myometrium, while progesterone exhibits no effect. The present results demonstrate that progesterone is responsible for the glycogen increase by stimulating the growth of endometrium—a glycogen-rich tissue. Since no endometrial tissue could be obtained from horns without decidual development, this study could not determine whether progesterone had any effect on glycogen deposition.