“…This is illustrated by studies showing that exogenous administration of hormones (i.e., oral contraceptives) and clinical situations in which the concentrations of hormones are altered (i.e., pregnancy and menopause) impact nicotine metabolism (Benowitz, LessovSchlaggar, Swan, & Jacob, 2006;Berlin, Gasior, & Moolchan, 2007;Dempsey, Jacob, & Benowitz, 2000;Selby, Hackman, Kapur, Klein, & Koren, 2001). Conversely, in a small clinical study, nicotine metabolism did not differ by menstrual phase in non-smoking women (n = 11) who received an infusion of nicotine and cotinine (Hukkanen, Gourlay, Kenkare, & Benowitz, 2005). These conflicting data indicate additional research is needed to more fully characterize the role of sex hormones on nicotine pharmacokinetics.…”