The influence of estradiol-17β dipropionate-progesterone ratios on uterine glycogen in the rat

Ovariectomized Holtzman rats were injected subcutaneously for three consecutive days with either oil, 1 μg of estradiol-17β dipropionate or 1 μg of estrogen plus 1, 5, 10 or 15 mg of progesterone. The animals were killed 24 hr after the last injection and uterine glycogen was determined. The estrogen increased uterine glycogen (both total and concentration) markedly over the control values, while all doses of progesterone given with estrogen suppressed the estrogen-induced total glycogen, but not the glycogen concentration. No dose of progesterone was more effective than another in altering the estrogen response. These data indicate that the E/P ratio is not as critical in evaluating uterine glycogen after three concurrent injections as it is after a single concurrent injection of the hormones.