Effects of the antidopaminergic drug veralipride on LH and PRL secretion in postmenopausal women

Patterns of LH and PRL secretion have been evaluated in 15 postmenopausal women before and after the chronic blockage of the D2 dopamine receptors with veralipride (100 mg twice daily, for 30 days). In addition, the possible influence of the antidopaminergic drug on the activity of the endogenous opioid system has been evaluated by the infusion of the opioid antagonist naloxone, performed before and during veralipride administration. Mean plasma LH levels were significantly blunted (p less than 0.05) and mean plasma PRL levels were significantly increased (p less than 0.001) by veralipride administration. The frequency of both LH and PRL secretory pulses was not modified, while the mean pulse amplitude of both hormones was significantly increased (p less than 0.05 for LH; p less than 0.001 for PRL) by veralipride administration. In untreated postmenopausal women naloxone infusion did not modify LH secretion. Following veralipride, the infusion of naloxone significantly increased (p less than 0.05) the mean plasma LH levels, had no influence on the frequency and significantly reduced (p less than 0.01) the amplitude of LH pulses, expressed as the percent increase from the nadir to the peak. Both before and after veralipride administration, naloxone failed to modify the pattern of PRL secretion. In untreated postmenopausal women, the percentage of concomitant PRL and LH pulses was significantly higher (p less than 0.001) during naloxone than during saline infusion, and this effect was amplified by veralipride administration (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)