Smokeless nicotine administration does not result in hypertension or a deterioration in glucose tolerance or insulin sensitivity in juvenile rats

We have previously reported that smokeless nicotine resulted in hypertension, but not a deterioration in glucose tolerance or insulin action in young adult male rats. To evaluate the effect of nicotine in juvenile animals, we studied 6-week-old male and female Sprague-Dawley rats and implanted 25-mg nicotine (N) or placebo (P) pellets. Weight gain was controlled by chow restriction in all 4 groups of rats. Males were generally heavier than females, both before and after N or P placement; there was no difference in weight between N and P groups for each sex. Systolic blood pressure, measured noninvasively, increased modestly, but not significantly, after N placement in both male and female rats. Glucose tolerance and insulin action were assessed by an oral glucose tolerance test (OGTT). Areas under the curve (AUC) were calculated for glucose (AUC(GLU)), insulin (AUC(INS)), and free fatty acids (FFA) (AUC(FFA)), Insulin action was calculated by several indices, which have correlated with more invasive studies. None of these metabolic parameters were significantly impacted by nicotine treatment, consistent with our observations in adult male rats. In summary, smokeless nicotine at this dose has no significant effect on observed cardiovascular or metabolic parameters in sexually immature male and female rats. Copyright 2003, Elsevier Science (USA). All rights reserved.