Abstract

Mass dose effects of the PET radioligands [11C] carfentanil and [11C] raclopride were determined on venous plasma cortisol and prolactin levels before and after tobacco smoking in overnight abstinent healthy male smokers. Methods:The total [11C] labeled and unlabeled doses of each ligand were used to assess the association between the doses of ligands and the hormone levels by linear regression analyses. Results:Peak cortisol levels after average nicotine (avnic) tobacco smoking were decreased with greater carfentanil doses (p = 0.03). The change in plasma cortisol levels after avnic smoking compared to before avnic smoking was also decreased with greater carfentanil doses (p = 0.003). Unexpectedly the changes in cortisol levels after denicitinized (denic) tobacco smoking compared to before denic smoking were increased with greater carfentanil doses (p = 0.04). No dose effects of raclopride were found on cortisol levels. Peak prolactin levels after avnic smoking were increased with greater raclopride doses (p = 0.003). The changes in prolactin levels after avnic smoking compared to before were also increased with greater doses of raclopride (p < 0.001). There was no effect of carfentanil on plasma prolactin. Conclusion:No correlations between the doses of the radioligands and the basal hormone levels were found. However in the presence of nicotine tobacco smoking the PET ligands had significant subtle clinical pharmacological effects on both cortisol and prolactin.

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