Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: February 22, 1996
Publication Date: N/A
Technical Abstract: The effect of estrogen treatment on endometrial protein secretion was investigated. Seventeen pregnant (P) and 18 pseudopregnant (PP) gilts received sham treatment or estrone (E1) or estradiol (E2) implants (5 mg/d release rate; 60 d release) on d 30 of pregnancy or pseudopregnancy. Blood samples were collected on d 30, 40, 50, and 60 for RIA determination of estrogens. On d 60, gilts were hysterectomized and endometrium adjacent t a placenta from each uterine horn was collected from P gilts. For PP gilts, each uterine horn was flushed and endometrial tissue was collected from each uterine horn. Endometrial estrogen concentrations were determined by RIA. Endometrium (500 mg) was incubated in MEM plus 50 uCi [3H]leucine to examine in vitro protein secretion. E1 and E2 treatments increased (P<.01) plasma and endometrial concentrations of each steroid. Endometrium from sham-treated P gilts secreted more (P<.01) nondialyzable macromolecules (NDM; 2.33+/-.17 vs 1.45+/-.19x10^7 DPM/g tissue), acid phosphatase (AP; 47.9 vs 28.7+/-4.5 umol/Pi/min/g tissue), and retinol binding protein (RBP; 66 vs 27+/-7 ug/g tissue) in culture than endometrium from sham-treated PP gilts. E1 treatment increased (P<.01) secretion of NDM for P gilts but not PP gilts (2.84 and 1.47+/-.17); E2 had no effect. Both E1 and E2 increased (P=.069) AP secretion for PP (37.8 and 38.8+/-4.5) but not P gilts (44.7+/-4.5 and 38.1+/-5.1). RBP was unaffected by either E1 or E2 treatment. Neither E1 nor E2 affected protein or AP in uterine flushings from PP gilts. In PP gilts, RBP in uterine flushings was decreased (P<.05) by E1 treatment compared to sham treatment (4 vs 9+/-2 mg). Thus, the conceptus increased endometrial protein secretion and estrogens did not mimic this effect.