Phenobarbital treatment enhances insulin-mediated glucose metabolism and improves lipid metabolism in the diabetic rat.
Previous studies with healthy volunteers and non-insulin-dependent diabetic (NIDDM) patients have shown a strong association between overall glucose metabolism and hepatic microsomal enzyme activity. In this study, the effects of 10-day oral administration of phenobarbital (PB), a potent inducer of the hepatic microsomal mixed-function oxidase system, on carbohydrate and lipid metabolism in the basal state and on glucose kinetics during submaximal hyperinsulinemic (5 mU.kg-1.min-1 insulin) clamps were investigated in nondiabetic rats and in rats made diabetic by the intravenous (IV) administration of either low-dose (40 mg/kg) or high-dose (55 mg/kg) streptozocin (STZ). In control rats receiving PB in drinking water (0.5 mg/mL), serum insulin and triglyceride levels were diminished without any change in glucose and cholesterol concentrations in the fed state. Administration of PB in drinking water (0.25 mg/mL) to both groups of diabetic rats decreased their water intake and serum triglyceride levels in the absence of an effect on glucose, insulin, and cholesterol concentrations in the fed state. However, fasting serum glucose levels and basal glucose turnover rates were lower in both groups of diabetic rats receiving PB. PB treatment increased the heparin-releasable lipoprotein lipase (LPL) activity of epididymal fat in both control and low-dose diabetic groups; this was not assessed in the high-dose diabetic group. Neither peripheral glucose utilization nor hepatic glucose production during submaximal insulin clamps was modified by PB treatment in nondiabetic rats. In contrast, PB administration enhanced insulin-mediated peripheral glucose utilization, as well as suppression of hepatic glucose production, in both low-dose and high-dose diabetic groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Venkatesan
N
N
Department of Medicine, Cedars-Sinai Medical Center, University of California at Los Angeles 90048.
Davidson
M B
MB
Simsolo
R B
RB
Kern
P A
PA
D000273:Adipose Tissue / Q000201:enzymology; D000284:Administration, Oral; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006003:Glycogen / Q000032:analysis / Q000378:metabolism; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D050356:Lipid Metabolism; D008071:Lipoprotein Lipase / Q000032:analysis; D008297:Male; D009132:Muscles / Q000737:chemistry / Q000378:metabolism; D010634:Phenobarbital / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013311:Streptozocin; D014280:Triglycerides / Q000378:metabolism; D014316:Tritium
D001786:Blood Glucose; D007328:Insulin; D014280:Triglycerides; D014316:Tritium; D013311:Streptozocin; D006003:Glycogen; D008071:Lipoprotein Lipase; D005947:Glucose; D010634:Phenobarbital