Increased triglyceride secretion rate and hyperinsulinaemia in ventromedial hypothalamic lesioned rats in vivo

The present study aimed to measure triglyceride secretion rate (TGSR) into the circulation in ventromedial hypothalamic (VMH) lesioned rats. Average gain of body weight in VMH lesioned rats was 72 +/- 6 g (mean +/- SE, n = 9) in a week; significantly greater than that in controls (6 +/- 2, n = 8, P less than 0.001). TGSR was determined under hexobarbital anaesthesia in fasted rats by measuring the increase in plasma concentration after the triglyceride removal mechanism was blocked by injecting Triton WR-1339. TGSR in VMH lesioned rats was 500 +/- 37 mg/dl of plasma/h; markedly higher than that in controls (239 +/- 12, P less than 0.001). Serum insulin concentration in VMH lesioned rats was 2.26 +/- 0.32 ng/ml; significantly higher than that in controls (0.83 +/- 0.08, P less than 0.001). There was a positive correlation between serum insulin concentration and TGSR in VMH lesioned rats (r = 0.709, P less than 0.05). The increased secretion rate of triglyceride in VMH lesioned rats is discussed in connection with the development of obesity in these rats.