Glucocorticoids and triglyceride transport: effects on triglyceride secretion rates, lipoprotein lipase, and plasma lipoproteins in the rat.
In order to elucidate the mechanism(s) of hyperlipidemia following glucocorticoid administration, dexamethasone (0.125 mg/Kg) was administered daily intramuscularly for 2 wk to male Sprague-Dawley rats and the effects on plasma triglyceride (TG) and cholesterol (Chol), lipoprotein neutral lipids, hepatic triglyceride secretion rates (TGSR; Triton), and epididymal fat lipoprotein lipase (LPL) were determined. Special measures were taken to maintain positive caloric balance and keep the weights of control and dexamethasone-treated animals comparable. Significant increases (p less than 0.001) in TG and very-low density lipoprotein (VLDL) triglyceride associated with no change in Chol and actual reduction in both triglyceride and cholesterol in low density lipoprotein (ldl) were observed in the steroid-treated animals. Dexamethasone treatment was associated with increased basal insulin and glucose levels, an insignificant increment in TGSR, and a highly significant reduction (p less than 0.001) in LPL. These findings suggest that glucocorticoid treatment increases splanchnic triglyceride production rates, but the resulting hypertriglyceridemia is primarily a consequence of impaired VLDL removal due to low adipose tissue LPL activity.
D000818:Animals; D002784:Cholesterol / Q000097:blood; D003907:Dexamethasone / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D006949:Hyperlipidemias / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism; D008074:Lipoproteins / Q000097:blood*; D008077:Lipoproteins, LDL / Q000097:blood; D008079:Lipoproteins, VLDL / Q000097:blood; D008297:Male; D051381:Rats; D014280:Triglycerides / Q000097:blood / Q000378:metabolism*
D007328:Insulin; D008074:Lipoproteins; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D014280:Triglycerides; D003907:Dexamethasone; D002784:Cholesterol; D008071:Lipoprotein Lipase; D005947:Glucose