Smokeless nicotine exposure has no lasting effect on fasting or postglucose circulation leptin in young rats

Nicotine exposure has been associated with weight loss and reduced weight gain. Previously, we have reported that nicotine exposure in rats is associated with reduced weight gain, unless diets are rigidly controlled. Leptin, a hormone released by adipose tissue, is believed to have appetite suppressant effects. We used a smokeless tobacco model to study leptin responses to nicotine or placebo treatment.

We studied 6-week-old male and female Sprague-Dawley rats, and implanted 50 mg of nicotine or placebo pellets. Weight gain was controlled by chow restriction in all four groups of rats. Systolic blood pressure was measured noninvasively, and glucose, insulin, free fatty acid, and leptin responses to an oral glucose load were determined at 8.5 weeks of age.

Males were generally heavier than females, both before and after nicotine or placebo placement; there was no difference in weight between nicotine and placebo groups for each sex. Blood pressure was slightly, but not significantly, increased by nicotine treatment. Glucose, insulin, free fatty acid, and leptin responses to glucose were essentially unaffected by nicotine treatment.

In summary, smokeless nicotine at this dose has no significant effect on fasting or postglucose leptin values in sexually immature male and female rats.