Marihuana Effects on Pituitary and Gonadal Hormones in Women

Abstract

A series of studies were carried out to assess the acute and chronic effects of marihuana smoking on pituitary and gonadal hormone levels in women. Plasma samples for analysis of luteinizing hormone (LH), estradiol, progesterone, and prolactin were obtained from 16 women prior to and following smoking one marihuana cigarette that contained 1.8% THC or a 1-g placebo cigarette. A small but statistically significant decrement (p < 0.02) in LH levels was observed following marihuana smoking in contrast to placebo smoking during the luteal phase of the menstrual cycle. However, the decrease in LH probably was not biologically significant since all LH levels were within the normal range for healthy adult women. Marihuana smoking was also followed by a small but statistically significant decrease in prolactin levels during the luteal phase of the menstrual cycle, but this probably was not biologically significant. The hormonal effects of daily marihuana smoking over 21 days were studied in 21 women who lived on a clinical research ward for 33 days. Women worked at a simple operant task to acquire marihuana cigarettes. Each marihuana cigarette contained 1.8% Δ9-THC. Blood samples for analysis of LH, estradiol, and progesterone were collected on alternate days before, during, and after marihuana smoking. Normal ovulatory menstrual cycles were observed, and there was no evidence of a marihuana dose-related suppression of ovulation or disruption of luteal phase function in women classified as heavy (6.1 ± 1.45 cigarettes per day), moderate (2.72 ± 0.16 cigarettes per day) or occasional (0.90 ± 0.22 cigarettes per day) marihuana smokers. These data indicate that smoking marihuana at the dose levels observed for 21 days did not disrupt the menstrual cycle in healthy adult women.