title: The effects of chronic nicotine on meal patterns, food intake, metabolism and body weight of male rats.
abstract: It is unclear what contribution food intake and metabolism have in causing weight loss after administering a dose of nicotine equivalent to smoking one to three packs of cigarettes per day because previous studies have been of a very short duration. To address this question, male Sprague Dawley rats were housed in computerized food intake modules and fed 45 mg pellets: Group 1 [nicotine injected with 1.4 mg/kg/day (free base), fed ad libitum]; and Group 2 [saline injected and pair-fed by computer with Group 2]; and Group 3 [saline injected (i.p.), fed ad libitum]. The rats received 4 equally spaced injections over the dark phase. Treatment consisted of: Phase 1 (nicotine or saline for 14 days), Phase 2 (all rats saline for 8 days and Phase 3 (pair-fed group "unyoked" for 6 days)). Nicotine inhibited food intake over the first 6 days. On termination of nicotine, there was no compensatory hyperphagia in either Groups 1 or 2; and their body weight was reduced starting on day 5 until day 28. In another study, rats were housed in an indirect calorimetry system. Saline or nicotine was injected for 14 days, as noted above; then all rats were injected with saline for 4 days and then no injections for 10 days to follow changes in body weight. Energy expenditure (Kcal/Kg(0.75)) was measured for 18 days. Nicotine significantly reduced food intake on 7 of 14 days of nicotine injections. The body weight of the nicotine injected rats was significantly reduced starting on day 3 until day 25. There were no differences in energy expenditures of the groups, which suggested that a decrease in food intake and not an increase in metabolism was the reason the rats lost weight after administering nicotine.
authors.affiliation: Department of Biomedical Science, Texas A&M University Health Science Center, Dallas, TX 75246, USA. lbellinger@bcd.tamhsc.edu
authors.forename: L L
authors.initials: LL
authors.lastname: Bellinger
authors.forename: P J
authors.initials: PJ
authors.lastname: Wellman
authors.forename: R B S
authors.initials: RB
authors.lastname: Harris
authors.forename: E W
authors.initials: EW
authors.lastname: Kelso
authors.forename: P R
authors.initials: PR
authors.lastname: Kramer
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects*; D004734:Energy Metabolism / Q000187:drug effects*; D005247:Feeding Behavior / Q000187:drug effects*; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D009538:Nicotine