Prolactin and pituitary-gonadal function in cigarette smoking infertile patients

Serum prolactin (PRL) was significantly lower in smokers, compared with non-smokers in 233 males and 250 females referred to our infertility clinics. In subjects smoking 10 cigarettes or more per day, the mean serum PRL was 22% and 20% lower in men and women, respectively. In cigarette smoking men serum testosterone was significantly higher and semen volume lower, while neither serum luteinizing hormone (LH) or follicle stimulating hormone (FSH), sperm density, motility of morphology differed between smokers and non-smokers. It is possible that the higher serum testosterone levels in smokers are due to their lower bodyweight, and that the lower semen volume may be due to an effect of nicotine on the contractility of the deferental ducts. Cigarette smoking may increase central dopaminergic tonus and reduce PRL levels, but it is unknown whether or not this is of biological significance in relation to reproductive function.