The effect of mesulergine on prolactin secretion and anterior pituitary cells morphology in diethylstilboestrol-treated female Wistar rats.

Mesulergine (Cu32-085) is an active semisynthetic ergot alkaloid with unusual biphasic antagonistic-agonistic effect on dopamine (DA) turnover in the rat striatum. The present study has been made to elucidate the influence of the long-term treatment of this drug on prolactin secretion and prolactin cells morphology in the female Wistar rats with experimentally-induced hyperprolactinemia. Additionally, the effect of this drug was compared with bromocriptine and pergolide activity, applied in the same experimental conditions. It has been shown that prolonged mesulergine treatment attenuated the stimulatory effect of stilboestrol on prolactin secretion in vivo. It also decreased mean prolactin cells density, above all cells and lactotroph mitotic indexes, estimated in immunohistochemically-stained slides. However, antiproliferative activity of Cu 32-085 was weaker, when compared with bromocriptine and pergolide.