Changes of blood flow in oestrogen-induced hyperplastic anterior pituitary lobe following bromocriptine...

Anterior pituitary hyperplasia and histologically verified adenomas were induced by diethylstilboestrol (DES) containing implants in a total of 104 female F344 rats. Thirty rats were used as controls. Blood flow in the anterior pituitary (PBF) was measured using the hydrogen clearance method. PBF was progressively reduced to 25% by DES in 13 weeks but the total adenohypophysial blood flow (flow as measured per unit weight multiplied by weight of the gland) was raised by 75%. Bromocriptine (BC, 1 mg/kg intravenously) reduced PBF by a maximum of 27% in tumour-bearing rats. When bromocriptine (1 mg/kg/day subcutaneously) was given for 7 days before the measurements the hyperplastic effect of DES on the pituitary gland and the total blood flow through the pituitary were both reduced by 23%. Reduction of blood supply may be one of the reasons that bromocriptine is clinically useful.