Bromocriptine reduces the size of cells in prolactin-secreting pituitary adenomas

Abstract

The morphometric analysis of the size of adenomatous prolactin cells shows that bromocriptine-induced cell shrinkage halts if treatment with the drug is discontinued for more than 2 days. Different cell components (nucleus, cytoplasm, nucleolus) do not react to treatment to the same extent.

Apoptosis in the Anterior Pituitary Gland of the Rat: Studies with Estrogen and Bromocriptine

“…A further ef fect of bromocriptine was the virtual elimination of cells with electron-dense cytoplasm and greatly dilated ER ('dark' cells) which were a prominent feature during es trogen withdrawal. Bromocriptine-induced loss of ER has been described in prolactin cells [26,27], but the re duction in numbers of 'dark' cells after 2 h exposure to bromocriptine is difficult to explain. The role of these cells is unknown [28].…”

Pituitary apoplexy during treatment of cystic macroprolactinomas with cabergoline

“…Moreover, treatment with DA causes late inhibition of prolactin gene transcription, and the resulting decrease in hormone synthesis causes further drop of PRL levels [40][41][42]. Additionally, DA promotes tumor regression due to lactotroph cell size reduction [43], and to degenerative and necrotic changes in tumor cells [44,45]. The lactotroph cell size reduction is caused by a decrease in cytoplasmic organelles [45][46][47][48][49], with concomitant increase in perivascular fibrous tissue [50], and these changes are reversible once the treatment with the drug is discontinued [51].…”

Effect of dopamine agonists on prolactinomas and normal pituitary assessed by dynamic contrast enhanced magnetic resonance imaging (DCE-MRI)

“…Prolactinomas can be primarily managed by medical therapy, but the mechanism by which the dopamine agonists (DA) have their tumour shrinkage effect is unclear. A number of reports have suggested that tumour regression was due to lactotroph cell size reduction [3][4][5], and subsequent ultrastructural studies have demonstrated a rapid involution of rough endoplasmic reticulum and Golgi apparatus, reversible after drug withdrawal [6].…”