Effects of 2-bromo-alpha-ergocryptine on the ultrastructure of anterior pituitaries in different experimental conditions.

The morphology of anterior pituitaries has been investigated by electron microscopy after administration of 2-bromo-alpha-ergocryptine (CB-154) in different experimental conditions. These include: a 1- to 5-week treatment (1 mg/kg BW, daily) to rats and a 5-week treatment (0.3 mg/kg BW, daily) to dogs, a single injection (2.5 mg/kg BW, 4 h before autopsy) or a 15-day treatment (1 mg/kg BW, daily) to hypophysectomized rats bearing an ectopic pituitary, a single injection (10 mg/kg BW, 4 h before autopsy) to rats bearing the experimental MtW 15 tumor and an in vitro experiment with fragments of a human GH producing adenoma incubated for 2 h in a medium containing CB-154 (1 microgram/ml). Some possible explanations for the structural changes observed after CB-154 treatment are offered.