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 i n 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 Psyc hiatric Association Diagnostic and Statistical Manual IV criteria for cocai ne abuse, and menstrual cycle phase was verified by estradiol and progester one measures. Baseline LH levels were equivalent between groups. Peak cocai ne levels did not differ significantly between men and women and averaged b etween 87 +/- 21 and 124 +/- 18 ng/ml after 0.2 mg/kg cocaine and between 2 27 +/- 22 and 287 +/- 21 ng/ml after 0.4 mg/kg cocaine. The lower dose of c ocaine (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 coc aine (0.4 mg/kg) stimulated significant increases in LH in men (P< 0.001) a nd in women at both phases of the menstrual cycle (P< 0.004-0.001). Althoug h cocaine's effects on LH in women were dose-dependent, there were no signi ficant differences as a function of menstrual cycle phase. LH remained sign ificantly elevated longer in men (32 min) than in women (8 and 12 min). Thi s gender difference in cocaine's potency in stimulating LH was unexpected.