Effects of cocaine on luteinizing hormone in women during the follicular and luteal phases of the menstrual cycle and in men.

Cocaine stimulates luteinizing hormone (LH) release in rhesus monkeys and in men, but its effects on LH in women are unknown. Cocaine (0.2 and 0.4 mg/kg i.v.) was administered to groups of follicular and luteal phase women (N = 22) and to men (N = 12) to examine the influence of gender and menstrual cycle phase on cocaine and LH interactions. All subjects met American Psychiatric Association Diagnostic and Statistical Manual IV criteria for cocaine abuse, and menstrual cycle phase was verified by estradiol and progesterone measures. Baseline LH levels were equivalent between groups. Peak cocaine levels did not differ significantly between men and women and averaged between 87 +/- 21 and 124 +/- 18 ng/ml after 0.2 mg/kg cocaine and between 227 +/- 22 and 287 +/- 21 ng/ml after 0.4 mg/kg cocaine. The lower dose of cocaine (0.2 mg/kg) significantly increased LH levels in men (P < 0.001) but not in women at either phase of the menstrual cycle. The higher dose of cocaine (0.4 mg/kg) stimulated significant increases in LH in men (P < 0.001) and in women at both phases of the menstrual cycle (P < 0.004-0.001). Although cocaine's effects on LH in women were dose-dependent, there were no significant differences as a function of menstrual cycle phase. LH remained significantly elevated longer in men (32 min) than in women (8 and 12 min). This gender difference in cocaine's potency in stimulating LH was unexpected.