Pergolide, a potent long-acting dopamine-receptor agonist

Area of Science:

• Endocrinology
• Pharmacology
• Neuroscience

Background:

• Prolactin is a hormone regulated by dopamine at the pituitary level.
• Disruptions in prolactin regulation are associated with various physiological and pathological conditions.
• Synthetic ergot derivatives are explored for their potential to modulate neuroendocrine functions.

Purpose of the Study:

• To investigate the effects of pergolide, a synthetic ergot, on plasma prolactin levels in normal subjects.
• To determine the dose-dependency and duration of pergolide's prolactin-lowering effects.
• To assess pergolide's specificity on other pituitary hormones and its interaction with prolactin-elevating agents.

Main Methods:

• Administration of single and multiple oral doses of pergolide (100-400 mcg and 150-250 mcg daily for 7 days) to normal subjects.
• Measurement of basal and stimulated plasma prolactin levels.
• Assay of plasma levels for follicle-stimulating hormone, luteinizing hormone, cortisol, growth hormone, and thyroid-stimulating hormone.

Main Results:

• Single and multiple doses of pergolide significantly reduced basal plasma prolactin levels in a dose-related manner, with effects lasting over 24 hours.
• A single 150 mcg dose of pergolide suppressed diurnal prolactin rhythms, including sleep-induced elevation.
• Pergolide dose-dependently inhibited perphenazine-induced prolactin elevation and did not affect other tested pituitary hormones.

Conclusions:

• Pergolide is a potent suppressor of prolactin secretion.
• The drug exhibits specificity for pituitary dopamine receptors involved in prolactin regulation.
• Pergolide's ability to normalize prolactin levels and rhythms suggests potential therapeutic applications in hyperprolactinemic states.