Venous plasma nicotine correlates of hormonal effects of tobacco smoking.

The present study resolves some of the discrepancies in the literature by correlating the effects of tobacco smoking on hormone release with venous plasma nicotine levels. Cortisol, prolactin, and beta-endorphin concentrations were measured. Habitual male tobacco users smoked denicotinized (very low nicotine) and average nicotine cigarettes in the morning after overnight tobacco abstinence. Several venous blood samples were withdrawn before and during the smoking sessions for subsequent analyses. The increases in plasma nicotine correlated well with plasma cortisol and prolactin levels (correlation coefficients r=0.66 and 0.53, respectively, p<0.05). This study quantifies the well known increase in plasma cortisol and prolactin after nicotine postsmoking for about 1h with peak plasma levels up to 35 ng/ml. Contrary to most abused drugs which release dopamine and decrease prolactin, nicotine concentration correlated with increased prolactin release. Increases in maximal plasma beta-endorphin levels following tobacco smoking were barely statistically significant with insufficient data to obtain a correlation coefficient.