Diminution of Hypertriglyceridemia-Induced Pressor Effect under Hyperinsulinemic Condition in Normal and Fructose-Induced Insulin Resistant Rats

Po-Shiuan Hsieh ； Wei-Tung Cheng ； Tse-Tsung Liu ； Ching-Hui Loh ； Bao-Chy Chang

《The Chinese Journal of Physiology》 50卷3期 (2007/06) Pp. 99-104

並列摘要

This study aimed to evaluate the effect of hyperinsulinemia on hypertriglyceridemia-induced pressor response in normal and fructose-induced insulin resistant rats. The rats were divided into six groups of eight rats and were fed a fructose-enriched diet (F(subscript INS), F(subscript INS+TG)) or a regular chow diet (C(subscript CTG), C(subscript INS), C(subscript INS+TG)) for 8 wks. The acute experiment was conducted at the end of wk 8 and consisted of a 30-min basal period and followed by a 120-min test period. After the basal period, somatostatin (1.3 g/kg/ min) combined with regular insulin (0.6 or 4 mU/kg/min) and variable glucose infusion were given to clamp euglycemia and euinsulinemia in C and CTG or euglycemia and hyperinsulinemia in C(subscript INS), C(subscript INS+TG), F(subscript INS) and F(subscript INS+TG). During test period, lipofundin (a triglyceride emulsion) was infused into C(subscript TG), C(subscript INS+TG), F(subscript INS+TG) and saline instead was infused into C, C(subscript INS), F(subscript INS). Plasma insulin and triglyceride levels were significantly higher in fructose-fed rats than in normal rats. During the test period, the lipofundin infusion (1.2 ml/kg/hr) increased plasma triglyceride levels by 368±39, 351±71 and 489±38 mg/dl compared with their baseline levels in lipid-infused groups. During the test period, low-dose insulin infusion kept plasma insulin at basal levels in C and CTG and high-dose insulin infusion increased plasma insulin levels about 6 times the baseline insulin level in C. Glucose infusion rate (GIR) was significantly higher in rats with high insulin infusion than those with low insulin infusion. The increase in GIR was lower in fructose-fed groups than in control groups under similar hyperinsulinemia. Rats with or without lipofundin infusion did not alter GIR during the test period. The present results demonstrated that hypertriglyceridemia-induced pressor response was diminished under hyperinsulinemic condition in both normal and fructose-induced insulin resistant rats.

並列關鍵字

hypertriglyceridemia ； hyperinsulinemia ； insulin resistance ； pressor response ； fructose-fed rats

參考文獻

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