Further evidence against dopamine deficiency as the cause of inappropriate gonadotropin secretion in patients with polycystic ovary syndrome.

Abstract

Previous studies suggested that a relative dopamine (DA) deficiency may explain the altered LH secretory dynamics that occur in patients with polycystic ovary syndrome (PCO). These studies included findings of decreased urinary excretion of homovanillic acid (HVA), a metabolite of DA, and increased urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG), the major brain metabolite of norepinephrine. To further explore the role of DA in these patients, disulfiram (250 mg) was administered daily for 2 weeks to alter the conversion of DA to norepinephrine and to increase both peripheral and central DA in patients with PCO and in normal women. LH pulse frequency and amplitude and the serum LH response to GnRH were assessed before and during disulfiram administration. A dopaminergic effect during disulfiram administration was evidenced by a decrease in serum PRL in the PCO patients and an increase in urinary HVA excretion and a decrease in the ratio of 3-methoxy-4-hydroxyphenylglycol to HVA in urine in both groups (all P less than 0.05). This increase in DA did not significantly alter the serum estrogen level, the mean serum LH level, LH pulse amplitude, or serum LH responses to GnRH in either the PCO patients or the normal women. These data suggest that increasing endogenous DA does not correct the inappropriate gonadotropin secretion characteristic of PCO and places further doubt on the importance of DA in explaining the altered LH secretory dynamics in these patients.