scholarly journals Association of Backfat Thickness with Postheparin Lipoprotein Lipase Activity and Very Low Density Lipoprotein-Subfractions in Growing Pigs

2001 ◽  
Vol 14 (11) ◽  
pp. 1592-1597 ◽  
Author(s):  
T. C. Loh ◽  
I. J. Lean ◽  
P. F. Dodds
Keyword(s):  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Growing Pigs ◽  
Backfat Thickness ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Lipoprotein Lipase Activity ◽  
Lipoprotein Subfractions

scholarly journals Deficiency of the Very Low-Density Lipoprotein (VLDL) Receptors in Streptozotocin-Induced Diabetic Rats: Insulin Dependency of the VLDL Receptor

Endocrinology ◽  
2005 ◽  
Vol 146 (8) ◽  
pp. 3286-3294 ◽  
Author(s):  
Tadao Iwasaki ◽  
Sadao Takahashi ◽  
Masao Takahashi ◽  
Yasuo Zenimaru ◽  
Takeshi Kujiraoka ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Lipoprotein Receptor ◽  
Lipoprotein Lipase Activity ◽  
Density Lipoprotein Receptor

Abstract Hyperlipidemia is a common feature of diabetes and is related to cardiovascular disease. The very low-density lipoprotein receptor (VLDL-R) is a member of the low-density lipoprotein receptor (LDL-R) family. It binds and internalizes triglyceride-rich lipoproteins with high specificity. We examined the etiology of hyperlipidemia in the insulin-deficient state. VLDL-R expression in heart and skeletal muscle were measured in rats with streptozotocin (STZ)-induced diabetes. STZ rats showed severe hyperlipidemia on d 21 and 28, with a dramatic decline in VLDL-R protein in skeletal muscle (>90%), heart (∼50%) and a loss of adipose tissues itself on d 28. The reduction of VLDL-R protein in skeletal muscle could not be explained simply by a decrease at the transcriptional level, because a dissociation between VLDL-R protein and mRNA expression was observed. The expression of LDL-R and LDL-R-related protein in liver showed no consistent changes. Furthermore, no effect on VLDL-triglyceride production in liver was observed in STZ rats. A decrease in postheparin plasma lipoprotein lipase activity started on d 7 and continued to d 28 at the 50% level even though severe hyperlipidemia was detected only on d 21 and 28. In rat myoblast cells, serum deprivation for 24 h induced a reduction in VLDL-R proteins. Insulin (10−6m), but not IGF-I (10 ng/ml), restored the decreased VLDL-R proteins by serum deprivation. These results suggest that the combination of VLDL-R deficiency and reduced plasma lipoprotein lipase activity may be responsible for severe hyperlipidemia in insulin-deficient diabetes.

Removal of triacylglycerols from chylomicrons and VLDL by capillary beds: the basis of lipoprotein remnant formation

2007 ◽  
Vol 35 (3) ◽  
pp. 472-476 ◽  
Author(s):  
F. Karpe ◽  
A.S. Bickerton ◽  
L. Hodson ◽  
B.A. Fielding ◽  
G.D. Tan ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Lipoprotein Lipase Activity ◽  
Remnant Lipoproteins ◽  
Triacylglycerol Content

The triacylglycerol content of chylomicrons and VLDL (very-low-density lipoprotein) compete for the same lipolytic pathway in the capillary beds. Although chylomicron triacylglycerols appear to be the favoured substrate for lipoprotein lipase, VLDL particles compete in numbers. Methods to quantify the specific triacylglycerol removal from VLDL and chylomicrons may involve endogenous labelling of the triacylglycerol substrate with stable isotopes in combination with arteriovenous blood sampling in humans. Arteriovenous quantification of remnant lipoproteins suggests that adipose tissue with its high lipoprotein lipase activity is a principal site for generation of remnant lipoproteins. Under circumstances of reduced efficiency in the removal of triacylglycerols from lipoproteins, there is accumulation of remnant lipoproteins, which are potentially atherogenic.

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