Nicotine (NIC) reduces body weight (BW) by decreasing food intake (FI).

Abstract

NIC is known to decrease FI and BW and BW remains attenuated long after FI has returned to normal. This suggests NIC might be increasing metabolism. To test this idea, male Sprague Dawley rats were housed in computerized FI modules and fed 45 mg pellets. Three groups of rats were used: (1) saline (SAL) injected (i.p.), fed ad lib; (2) NIC injected (i.p.) 1.4 mg/kg/day (free base), fed ad lib; and (3) SAL injected (i.p.), pair-fed (PF) by computer with group 2. The rats received 4 equally spaced injections over the dark phase. The three groups were given: (1) NIC or SAL for 14 days then, (2) SAL only for 8 days; and then (3) SAL for 15 days with the PF group being “unyoked” and fed ad lib. Results show NIC reduced ( P <0.01) FI over the first 6 days with FI recovering to group 1 levels by day 9. FI suppression resulted from a persistent decrease in meal size and recovery of FI was caused by an increase in meal frequency. On termination of NIC, group 2 showed a reversal in meal patterns. Despite the lower BW upon termination of NIC a compensatory hyperphagia was not observed in either group 2 or 3. BW was attenuated ( P <0.05) by day 2 and was reduced ( P <0.05) similarly in groups 2 and 3 until day 30. Interestingly, the PF, but not the NIC, group's BW remained lower ( P <0.05) on day 37. Thus the BW of the NIC group only slowly returns to normal after termination of NIC and during the duration of the experiment the BW of the PF group did not recover to control levels even after they were “unyoked”. Supported by TAM-HSC Vice President's Research Funds.