Decreased triglyceride-rich lipoproteins in transgenic skinny mice overexpressing leptin

2001 ◽  
Vol 280 (2) ◽  
pp. E334-E339 ◽  
Author(s):  
Naoki Matsuoka ◽  
Yoshihiro Ogawa ◽  
Hiroaki Masuzaki ◽  
Ken Ebihara ◽  
Megumi Aizawa-Abe ◽  
...  

Leptin is an adipocyte-derived circulating satiety factor with a variety of biological effects. Evidence has accumulated suggesting that leptin may modulate glucose and lipid metabolism. In the present study, we examined lipid metabolism in transgenic skinny mice with elevated plasma leptin concentrations. The plasma concentrations of triglycerides and free fatty acids in transgenic skinny mice were 71.5 ( P < 0.01) and 89.1% ( P < 0.05) of those in their nontransgenic littermates, respectively. Separation of plasma into lipoprotein classes by ultracentrifugation revealed that very low density lipoprotein-triglyceride concentrations were markedly reduced in transgenic skinny mice relative to the controls. The clearance of triglycerides estimated by a fat-loading test was enhanced in transgenic skinny mice; the triglyceride concentration in transgenic skinny mice 3 h after fat loading was 39.7% ( P < 0.05) of that of their nontransgenic littermates. Postheparin plasma lipoprotein lipase activity increased 1.4-fold ( P < 0.05) in transgenic skinny mice. Our data demonstrated a significant reduction in plasma triglyceride concentrations, accompanied by increased lipoprotein lipase activity in transgenic skinny mice overexpressing leptin, suggesting that leptin plays a role in long-term triglyceride metabolism.

2002 ◽  
Vol 277 (12) ◽  
pp. 10037-10043 ◽  
Author(s):  
Hiroaki Yagyu ◽  
E. Peer Lutz ◽  
Yuko Kako ◽  
Steven Marks ◽  
Yunying Hu ◽  
...  

Endocrinology ◽  
2005 ◽  
Vol 146 (8) ◽  
pp. 3286-3294 ◽  
Author(s):  
Tadao Iwasaki ◽  
Sadao Takahashi ◽  
Masao Takahashi ◽  
Yasuo Zenimaru ◽  
Takeshi Kujiraoka ◽  
...  

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 (&gt;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.


Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 2003
Author(s):  
Risa Araki ◽  
Akira Yada ◽  
Hirotsugu Ueda ◽  
Kenichi Tominaga ◽  
Hiroko Isoda

The effectiveness of anthocyanins may differ according to their chemical structures; however, randomized clinical controlled trials (RCTs) or meta-analyses that examine the consequences of these structural differences have not been reported yet. In this meta-analysis, anthocyanins in test foods of 18 selected RCTs were categorized into three types: cyanidin-, delphinidin-, and malvidin-based. Delphinidin-based anthocyanins demonstrated significant effects on triglycerides (mean difference (MD): −0.24, p < 0.01), low-density lipoprotein cholesterol (LDL-C) (MD: −0.28, p < 0.001), and high-density lipoprotein cholesterol (HDL-C) (MD: 0.11, p < 0.01), whereas no significant effects were observed for cyanidin- and malvidin-based anthocyanins. Although non-significant, favorable effects on total cholesterol (TC) and HDL-C were observed for cyanidin- and malvidin-based anthocyanins, respectively (both p < 0.1). The ascending order of effectiveness on TC and LDL-C was delphinidin-, cyanidin-, and malvidin-based anthocyanins, and the differences among the three groups were significant (both p < 0.05). We could not confirm the significant effects of each main anthocyanin on glucose metabolism; however, insulin resistance index changed positively and negatively with cyanidin- and delphinidin-based anthocyanins, respectively. Therefore, foods containing mainly unmethylated anthocyanins, especially with large numbers of OH groups, may improve glucose and lipid metabolism more effectively than those containing methylated anthocyanins.


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