Measurement and characterization of swine uterine estradiol receptors: the effects of puberty induction on estradiol receptors and corpus luteum function.
Two types of cytoplasmic 17 beta-estradiol (E2) binding activity were identified and characterized in the uteri of pregnant, cycling and prepubertal, cycle-induced (400 IU pregnant mare's serum gonadotrophin (PMS) + 200 IU human chorionic gonadotrophin (hCG)) gilts. Overall, type I affinity and capacity were Kd 1.94 +/- 0.51 nM and 5.410 +/- 1.09 pmol/mg protein, respectively; type II apparent dissociation constant and capacity were Kd 21.34 +/- 6.83 nM and 62.58 +/- 15.96 pmol/mg protein, respectively. Cytoplasmic luteal E2 receptors were undetectable in all groups. Uterine E2 receptor activity was eluted from diethylaminoethyl columns by a 0.05-0.15 M KCl gradient. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated a molecular weight of 70 400-79 000. Excluding gilts with cystic ovarian follicles (16.67%), prepubertal gilts treated with PMS + hCG versus cycling sows had lower serum progesterone on days 6 and 9-13 of the estrous cycle and lower 13,14-dihydro-15-keto prostaglandin F2 alpha levels on days 0-9 and 13-17 of the cycle. Implants, containing 200 mg estrone inserted subcutaneously on days 12-19 after PMS + hCG treatment in gilts, had no discernible effects on these parameters. These results indicate that the diminished reproductive capacity of the gilt, in which cycle activity is induced by PMS + hCG, is likely due to decreased luteal progesterone secretion. Preliminary data also suggest that the lack of E2 receptors may contribute to the low reproductive performance in gilts with cystic ovarian follicles.
D000818:Animals; D002848:Chromatography, DEAE-Cellulose; D003338:Corpus Luteum / Q000502:physiology*; D004343:Drug Implants; D004970:Estrone / Q000097:blood / Q000494:pharmacology; D005260:Female; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011863:Radioimmunoassay; D011959:Receptors, Estradiol / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D013552:Swine / Q000378:metabolism*; D014599:Uterus / Q000378:metabolism*
D004343:Drug Implants; D011959:Receptors, Estradiol; D011960:Receptors, Estrogen; D004970:Estrone; D011374:Progesterone