Effect of dihydroergocristine administration on serum prolactin and growth hormone levels in normal, hyperprolactinaemic, and acromegalic subjects: further evidence for pituitary dopamine deficiency in these conditions
Ferrari, C.; Romussi, M.; Benco, R.; Rampini, P.; Mailland, F.
Acta Endocrinologica 103(1): 1-6
1983
ISSN/ISBN: 0001-5598 PMID: 6407250 Document Number: 202411
To evaluate further the pharmacological properties of dihydroergocristine in vivo, this drug (6 mg) or a placebo were administered orally on separate days to 11 healthy controls, 11 patients with adenomatous (4) or idiopathic hyperprolactinemia (7) and 5 acromegalics with raised serum prolactin [Prl] levels; serum Prl and growth hormone (GH) were measured at hourly intervals for 6 h. Dihydroergocristine induced a significant Prl decrease vs. placebo in hyperprolactinemics and acromegalics, but had no effect in healthy subjects. GH levels did not change in normals and hyperprolactinemics, but decreased significantly in acromegalics. The Prl decrease induced by dihydroergocristine was significantly lower than that induced by L-dopa (500 mg orally) in 9 hyperprolactinemics so tested. Nomifensine (200 mg orally) administered to 7 hyperprolactinemics had no effect. Similarly, the GH decrease induced by the drug in acromegalics was significantly lower than that exerted by L-dopa, while nomifensine had no effect. Five hyperprolactinemic patients were also given 12-18 mg dihydroergocristine daily for 3 mo. There was evidence of partial or total Prl suppression and resumption of menses in all patients. Dihydroergocristine is a relatively weak dopamine agonist at pituitary level and oral doses, insufficient to exert Prl-lowering activity in normal subjects, are able to inhibit Prl and GH release in hyperprolactinemics and dopamine-responsive acromegalics. These findings further support the existnece of a denervation supersensitivity to dopamine in these conditions, in which dopamine deficiency at pituitary level has been suggested on the basis of other experiments.