PLASMA AND UTERINE CORTISOL, PROGESTERONE AND PROTEIN-CHANGES IN PSEUDOPREGNANT GILTS TREATED WITH HYDROCORTISONE ACETATE

To determine the effects of cortisol concentrations during pregnancy, gilts, made pseudopregnant through twice daily administration of 5 mg estradiol benzoate on Days 11 to 15 (Day 0 first day of estrus), recei ved either 5 mg/kg body weight of hydrocortisone acetate (HA) in sesam e oil (n=5) or sesame oil alone (n=6) twice daily on Days 21 to 30. Bl ood samples (20 ml) were collected on Days 11, 21 and 31. Uterine flus hings were obtained surgically on Day 31. The HA-treated gilts had hig her (P<0.01) plasma cortisol (295.7 vs 35.6 ng/ml) and lower (P<0.01) plasma progesterone (8.9 vs 17.8 ng/ml) concentrations than did contro ls. Uterine flushings recovered from HA-treated gilts had significantl y (P<0.01) higher cortisol (9.9 vs 5.6 ng/ml), lower progesterone (2.1 vs 6.8 ng/ml) and lower total protein (8.3 vs 21.4 mg/ml) levels than the control animals. Cortisol measured in the uterine flushings of th e gilts was more than 85% unbound. Plasma corticosteroid binding globu lin binding capacity was lower (P<0.05) in HA-treated gilts (7.4 nmol/ 1) than in the control (38.7 nmol/1) animals on Day 31. Corpora lutea (CL) number and weight were lower (P<0.05) in HA-treated than control gilts. However, progesterone concentration per CL did not differ betwe en the 2 groups. These results indicate that elevated cortisol levels can alter endocrine and uterine functions related to pregnancy using t he pseudopregnant gilt as a model.