Abstract
TWELVE gilts were ovariectomized on day 4 of the estrous cycle and randomly assigned to receive either progesterone (P, 2.2 mg/kg), estrogen (E, 1.1 µg/kg), progesterone and estrogen (PE), or corn oil (C, 4 ml) daily until day 15 of the estrous cycle to determine the key hormone(s) responsible for porcine uterine protein secretions. The gilts were laparotomized on day 15 and the uterine protein secretions obtained by flushing each uterine horn with 20 ml of 0.33 M NaCl. Total protein recovered was 13.7, 14.1, 77.5 and 167.3 mg for the C, E, P and PE treated gilts, respectively. Sephadex G-200 protein profiles for P and PE treated gilts were similar to those for intact controls; however, those from C and E treated gilts revealed only three of the five expected protein fractions. In a subsequent experiment, 14 gilts were ovariectomized on day 4 and treated with P (2.2 mg/kg) until either day 7, 9, 11, 13, 15, 17 or 19 of the estrous cycle to compare the pattern of uterine protein secretion with that for intact controls. Total protein recovered at surgery was 7.5, 9.9, 12.0, 20.5, 77.5, 217.6 and 361.4 mg on days 7, 9, 11, 13, 15, 17 and 19 after the onset of estrus, respectively. Quantitative and qualitative aspects of the P induced secretions were similar to that for intact non-mated gilts up to day 15. However, on days 17 and 19, total protein was greater in the P treated gilts and all five uterine protein fractions were present. These data indicate that progesterone is the essential hormone which regulates the qualitative and quantitative aspects of porcine uterine protein secretions during the estrous cycle and presumably during pregnancy. Copyright © 1973. American Society of Animal Science . Copyright 1973 by American Society of Animal Science.