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), received either 5 mg/kg body weight of hydrocortisone acetate (HA) in sesame oil (n=5) or sesame oil alone (n=6) twice daily on Days 21 to 30. Blood samples (20 ml) were collected on Days 11, 21 and 31. Uterine flushings were obtained surgically on Day 31. The HA-treated gilts had higher (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 controls. Uterine flushings recovered from HA-treated gilts had significantly (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 the gilts was more than 85% unbound. Plasma corticosteroid binding globulin 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 between the 2 groups. These results indicate that elevated cortisol levels can alter endocrine and uterine functions related to pregnancy using the pseudopregnant gilt as a model.