Gonadotropin response to synthetic gonadotropin hormone-releasing hormone (GnRH) in heroin addicts

To determine whether the pituitary-gonadal deficiency in heroin addicts is related to heroin's effect on the hypothalamus, the authors administered gonadotropin hormone-releasing hormone (GnRH) to 10 male heroin addicts and 5 controls and measured follicle-stimulating hormone (FSH) and luteinizing hormone (LH) response. Basal FSH and LH levels were significantly lower in addicts; after GnRH stimulation the addicts' FSH and LH values increased but not significantly compared to controls. The difference between the two groups' response was highly significant. The authors suggest that heroin causes an incomplete blocking of gonadotropin secretion at the pituitary level, inducing a hypophyseal-gonadal deficiency and a long-lasting depletion of the endogenous releasing factor, which accounts for the reduced response to GnRH.