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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In normal individuals, insulin regulates lipoprotein metabolism. It increases hepatic triglycerides (TG) secretion and makes VLDL and chylomicrons post prandial removal easy by stimulating adipose tissue lipoprotein lipase (LPL). Insulin activity and cholesterol rich lipoprotein is more complicated: by its action on VLDL and chylomicrons turn-over, it influences LDL and HDL formation. It regulates cellular cholesterol pool at different levels: stimulation of LDL receptor, but also of HMG CoA reductase. Controlling LCAT, in participates in cholesterol removal by HDL. In insulin dependent diabetes, lack of adipose tissue LPL stimulation augments triglycerid-rich lipoproteins, by slowing their catabolism, resulting in a weak increase of LDL and a lowering of HDL. In non insulin dependent diabetes with hyperinsulinism, VLDL are elevated because of insulin stimulation of triglycerid hepatic production. LDL are increasing. HDL status remains discussed: HDL cholesterol is low but HDL triglycerid is high, there is no known disturbance of apo A level. In the two types of diabetes, although mechanism is different, perturbation of lipoprotein metabolism may account for the atherogenicity of this disorders.
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PMID:[Insulin and the metabolism of lipoproteins]. 634 30

The effects of treatment on plasma total triglyceride, total cholesterol, and plasma postheparin lipase activities have not been evaluated in non-insulin-dependent diabetic (NIDD) subjects without a coexisting familial lipid disorder. In 49 untreated NIDD subjects, there was a linear relationship between glycosylated hemoglobin (GHb) and triglyceride (r = 0.35, P less than 0.02). This correlation was improved after adjusting for the effects of obesity by a partial correlation analysis. After therapy, there was a significant relationship between the change in GHb and the change in triglyceride. To determine whether changes in lipid removal from plasma may contribute to the decrease in plasma lipid concentrations during treatment, the plasma postheparin lipoprotein lipase and hepatic lipase activities were evaluated in a subgroup (N = 8) of these NIDD subjects before and after 1 and 3 mo of therapy. Plasma postheparin hepatic lipase activity in the NIDD subjects was not different from that observed in six normal control subjects and did not change during therapy. In contrast, plasma postheparin lipoprotein lipase activity was lower in the untreated NIDD subjects than in the control subjects. Analysis of the two phases (early and late) of the postheparin lipoprotein lipase activity in plasma showed that the abnormal early phase in untreated NIDD corrected to normal values in less than a month, but the late phase was not corrected until the 3-mo measurement. These findings suggest that some NIDD subjects have a defect in heparin releasable lipoprotein lipase activity, which is reversed with improved glycemic control.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1983 Jun
PMID:The response of plasma triglyceride, cholesterol, and lipoprotein lipase to treatment in non-insulin-dependent diabetic subjects without familial hypertriglyceridemia. 635 82

In order to further investigate the behaviour of high density lipoproteins in diabetes mellitus, we studied HDL subclasses, HDL2 and HDL3, in 10 patients with newly detected, untreated insulin-deficient diabetes before starting insulin treatment and after getting a good metabolic control. We used the extractive method of Abell to determine HDL-cholesterol after LDL and VLDL precipitation with polyanions and HDL3-cholesterol after HDL2 precipitation with dextransulphate 15,000 m.w. After insulin therapy, we observed a significant increase in HDL-cholesterol and a decrease in serum triglycerides. Only HDL2-cholesterol, but not HDL3-cholesterol, raised; moreover, we found a significant inverse relationship between HDL-cholesterol (and also HDL2-cholesterol) and triglycerides. So, we think that an increase of lipoprotein lipase activity, owing to insulin treatment, could account for our results.
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PMID:[Changes in HDL subfractions in patients with type I diabetes mellitus before and after metabolic control]. 636 16

Fasting in normal rats produced a fall in hepatic triglyceride lipase (H-TGL) activity as well as lipoprotein lipase (LPL) activities of adipose tissue and psoas minor muscle. On the other hand, LPL activities of heart and diaphragm were not decreased by fasting; the former, in fact, was increased significantly. Changes in tissue specific lipase activity caused by withdrawal of insulin from insulin-treated diabetic animals paralleled in direction the changes induced by starvation of normal rats. Furthermore, it was shown in the present paper that the tissue specific lipase activity of diabetic rats became stuck in the starve phase of the starve-feed cycle regardless of dietary intake. The changes of the tissue specific lipase activities, especially of liver, adipose tissue and heart, appeared to coincide with those of plasma insulin levels. These results strongly suggest that the tissue specific lipase system is under hormonal regulation by insulin. Streptozotocin diabetes produced hypertriglyceridemia. The possible mechanism of the hypertriglyceridemia in diabetic animals was discussed in connection with the role of the tissue specific lipase system in the serum triglyceride metabolism.
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PMID:The effects of streptozotocin diabetes on tissue specific lipase activities in the rat. 638 14

Insulin deficiency was produced by streptozotocin in young (5-6 wk old) male rats, and measurements were made of plasma triglyceride and glucose concentrations and of lipoprotein lipase (LPL) activity of adipose tissue (epididymal) and muscle (gastrocnemius and soleus). Rats with streptozotocin-induced diabetes underwent a significant reduction in adipose tissue LPL activity (both total and heparin releasable), but the fall in LPL activity in these rats bore little relationship to their rise in plasma triglyceride concentration. Furthermore, muscle LPL activity was essentially unchanged in diabetic rats. Qualitatively similar changes were observed when measurements were made at either 8 a.m. (after the normal evening access to food) or 2 p.m. (6 h after food withdrawal). It is concluded that the hypertriglyceridemia that occurs secondary to insulin deficiency is not a simple function of decreased tissue LPL activity.
Diabetes 1980 Aug
PMID:Dissociation between plasma triglyceride concentration and tissue lipoprotein lipase deficiency in insulin-deficient rats. 644 94

Streptozotocin diabetes [45 mg/kg] in rats fed on a standard diet, with insulin substitutional therapy - 66 [nkat/kg]/d [[4 U/kg b.w.]d] for the first 3 days - led during an 8 days' experiment to marked hypertriglyceridaemia [4.86 mmol/l] and to triglyceride accumulation in the liver [22.35 mmol/kg]. The endogenous triglyceride secretion rate, studied by means of a Triton WR 1339 block of lipoprotein lipase, was almost 30 % lower in diabetic rats. The half-time of plasma 14C-triglycerides [labelled endogenously with 14C-1-palmitic acid] almost doubled and the fractional turnover rate fell to half the value in the control animals. Hypertriglyceridaemia in diabetic rats [60 % insulin deficiency] is caused by slower removal of lipoprotein triglycerides from the plasma space, owing to reduced lipolytic activity in the peripheral tissues.
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PMID:Kinetics of plasma triglycerides in rats with streptozotocin diabetes. 645 36

Beta 2-glycoprotein-I (apolipoprotein H) is an activator of the lipoprotein lipase. The concentration of beta 2-glycoprotein-I in the blood serum was determined with the help of the radial immunodiffusion. In patients with hyperlipoproteinaemia of type IIa and IIb, arteriosclerotic obstructive disease or diabetes mellitus the beta 2-glycoprotein-I-concentrations were increased. In hyperlipoproteinaemia of type IV can be concluded to a relative beta 2-glycoprotein-I-deficiency.
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PMID:[Beta 2 glycoprotein I analysis in patients with hyperlipoproteinemia, arteriosclerotic occlusive disease and diabetes mellitus]. 661 92

Plasma triacylglycerol and phospholipid concentrations were increased in fasting and diabetic sheep compared with fed animals. Secretion was measured in these animals using Triton WR1339 to block lipoprotein lipase. Triacylglycerol secretion was lowest in fed animals and, unlike non-ruminant species, increased by fasting and diabetes. These changes were in proportion to plasma free fatty acid concentration. However, no effect of Triton was found on plasma phospholipids under any of the conditions studied. It is suggested that the low rate of triacylglycerol secretion in normal animals is due to the limiting membrane found in the liver sinusoid of the sheep and that the greater rate in fasting and diabetes reflects the increased mass of intrahepatic triacylglycerol.
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PMID:Plasma triacylglycerol secretion in sheep. Paradoxical effects of fasting and alloxan diabetes. 661 61

Hyperlipidemia is common in diabetic patients. While our understanding of lipid and lipoprotein metabolism in diabetes is incomplete, a pathophysiologic approach to this problem is presented. It is based on the recognition that diabetes is metabolically heterogeneous. Thus the roles of insulin deficiency, insulin resistance, obesity, and genetic factors are discussed in relation to their effects on lipoprotein production and catabolism. The most important defect in insulin-deficient subjects appears to be a deficiency of lipoprotein lipase, which is responsible for the removal of the triglyceride-rich lipoproteins. In non-insulin-dependent subjects there is evidence for a removal defect as well as, in some patients, for overproduction of VLDL-triglyceride. Cholesterol levels may be elevated and it is important to distinguish between VLDL, LDL, and HDL as the causes for these increases. HDL-cholesterol levels may be increased in insulin-dependent subjects, whereas they may be decreased in obese non-insulin-dependent patients. Mild elevations of LDL-cholesterol may occur in inadequately controlled type I and II diabetic patients, while elevated VLDL may raise the serum cholesterol in addition to the triglyceride levels. The rationale for therapy is based on the complications of severe hypertriglyceridemia and the risk of occlusive atherosclerosis. Management is directed at improving glycemic control, altering dietary composition, and reducing calories in obese patients. Improved glycemic control is effective in reducing triglyceride and cholesterol levels in insulin-deficient subjects. The response of the non-insulin-dependent diabetic patient to improved control may be complicated by associated obesity or familial hyperlipidemia. The advantages and disadvantages of fat versus carbohydrate restriction in the diet are discussed. Finally, resistant hyperlipidemia may require drug therapy. Diabetic hyperlipidemia should be viewed as resulting from an interaction between the diabetic syndrome, the genetic background of the patient, and the environment.
Diabetes Care
PMID:Lipid disorders in diabetes. 675 32

Plasma lipids and lipoproteins were studied in 26 nonobese diabetic patients, either newly diagnosed or unsatisfactorily controlled by oral antidiabetic treatment. Measurements were performed before and 3-4 mo after the institution of insulin treatment. In a subgroup of seven patients, the activities of lipoprotein lipase (LPL) and hepatic lipase (HL) in postheparin plasma and the elimination rate of exogenous triglyceride were also monitored. After beginning insulin treatment, diabetic control was improved as demonstrated by decreasing levels of HbA1. Mean plasma cholesterol and triglyceride levels decreased by about 10% (P less than 0.01) and 40% (P less than 0.05), respectively. The decrease in plasma cholesterol was largely accounted for by a fall in LDL cholesterol levels (-8%, P less than 0.05), while plasma HDL cholesterol concentrations increased by about 12% (P less than 0.01). The elimination rate of exogenous triglycerides increased significantly. There was a suggestive, but not significant, increase in LPL activity while the HL activity remained unchanged. It is concluded that the improved diabetic control after institution of insulin treatment results in a significant improvement of the plasma lipoprotein profile. Since the improvement of the lipoprotein pattern is not strictly correlated to the amelioration of indices reflecting glucose transport, we suggest that the plasma lipoprotein pattern may provide an additional tool for monitoring the degree of control in diabetes mellitus.
Diabetes Care
PMID:Improvement of the plasma lipoprotein pattern after institution of insulin treatment in diabetes mellitus. 675 40


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