changes in biochemical parameters of carbohydrate metabolism following fenfluramine adminis tration in rats

fenfluramine, an anorexigenic agent, is widely used in the treatment of obesity. besides its anorectic effect, it may also have some effects on general metabolism with the consequence of weight loss. in this study, the effect of fenfluramine on the concentrations of some parameters related to carbohydrate metabolism was investigated. it was shown that the serum insulin level was reduced by 41 %, four hours after fenfluramine administration, which was accompanied by the elevation of serum glucose levels by 26%. the liver glycogen content showed a transient reduction, but reached the control level four hours post-treatment. corticosterone levels were elevated immediately, followed by a 20% reduction after four hours. the short-term effects of fenfluramine on thyroid hormones were not statistically significant. administration of fenfluramine for two weeks did not change the glycogen content of the liver significantly, but 64% and 103% increases were observed after four and six weeks of drug treatment, respectively. insulin levels showed a gradual increase so that by the end of six weeks, 153% increase in insulin level was observed. no significant changes in serum glucose levels were seen during the period of treatment. corticosterone concentration remained unchanged up to four weeks of treatment but a 32% reduction was seen after six weeks. the levels of t4 and t3 showed a transient increase, followed by a significant decrease after six weeks of treatment. it is concluded that fenfluramine has some important metabolic effect that is related to its action in decreasing food intake and weight loss.