The effect of 2-Br-α-ergocryptine on the hepatic steroid metabolism and serum pituitary hormone levels in normal rats and rats with an ectopic pituitary

The effect of a dopaminergic agonist, CB-154 (2-Br-α-ergocryptine), on the hepatic steroid metabolism in normal male and female rats, and in hypophysectomized male animals bearing an implanted pituitary under the kidney capsule, has been investigated. The serum levels of the four pituitary hormones LH, FSH, prolactin and growth hormone, were also measured. In normal animals, CB-154 reduced the serum level of prolactin without significantly affecting levels of LH, FSH or growth hormone and without masculinizing hepatic steroid metabolism of female rats of feminizing hepatic steroid metabolism of male rats. Implantation of a pituitary gland from age-matched female rats in hypophysectomized male rats caused an increase in prolactin and growth hormone levels in serum and a shift towards a more feminine type of steroid metabolism. Treatment with CB-154 reduced the prolactin level without affecting LH, FSH or growth hormone levels and without masculinizing hepatic steroid metabolism. In conclusion, the drug, CB-154, causes a marked and selective decrease in circulating prolactin levels without affecting the sex differentiation of hepatic steroid metabolism thus indicating that these two parameters are not related. A certain correlation between growth hormone levels and degree of femininity of steroid metabolism was seen but the significance of this is debatable.