Effect of bromocryptine on 20 alpha-hydroxysteroiddehydrogenase regulation in the corpus luteum of the pregnant rat. 
Pregnant Sprague Dawley rats were passively immunized with antiserum to bovine luteinizing hormone (anti-LH) on day 10 of pregnancy, and treated with 1 mg/day or 1.5 mg/day of the prolactin (Prl) inhibitor bromocryptine (BEC) between days 10 to 12 or 9 to 12, respectively.  On day 12 a laparotomy was performed to assess the state of pregnancy and to remove the ovaries for histochemical detection of 20 alpha-hydroxysteroiddehydrogenase (20 alpha-OHSD) in the corpora lutea of pregnancy.  In a second experiment pregnant rats were treated with 1.5 mg BEC/day from days 17 to 22, checked for foetal state and ovariectomized on day 22 before giving birth.  Treatment with BEC in effective doses did not interfere with anti-LH-induced termination of pregnancy and consequent reappearance of 20 alpha-OHSD activity on day 12, or with spontaneous recurrence of enzyme activity at the end of gestation.  It is concluded that Prl has no direct and immediate role in 20 alpha-OHSD regulation, at least on day 12, although substitution by endogenous rat placental lactogen at the end of pregnancy cannot be excluded.