Nausea, Cigarette Smoking, Nicotine, and Pituitary Hormone Release
This laboratory has previously reported increases in arginine vasopressin, neurophysin I, and beta-endorphin/beta-lipotropin in conjunction with relatively high plasma nicotine levels in subjects not experiencing nausea. The present study further explores the hormonal and neuropeptide responses provoked by nicotine from smoking. Nausea was induced in deprived smokers by having them smoke 2 high-nicotine cigarettes (2.87 mg.) in succession. Subjects who reported nausea showed a less selective release of pituitary hormones than previously observed at sub-nausea: Plasma levels of adrenocorticotropic hormone, arginine vasopressin, beta-endorphin/beta-lipotropin, growth hormone, neurophysin I, and prolactin increased over baseline; no increases were seen in follicle-stimulating hormone, luteinizing hormone, or thyroid-stimulating hormone. Nausea and significantly elevated pituitary hormone release were consistently associated with plasma nicotine levels exceeding 60 ng/ml produced by smoking high-nicotine cigarettes, but did not occur in response to low-nicotine (0.48 mg.) cigarettes (plasma nicotine levels below 10 ng/ml). Because the hormonal profile associated with nicotine-induced nausea resembles that of nausea produced by other manipulations (motion sickness, administration of other drugs), it is likely that the observed hormonal pattern at this level of stimulation is characteristic of nausea and not unique to nicotine.