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Query: UMLS:C0020473 (hyperlipidemia)
 15,891 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:Glucocorticoids and triglyceride transport: effects on triglyceride secretion rates, lipoprotein lipase, and plasma lipoproteins in the rat. 17 40

There are several causes for hyperlipemia in the diabetic: (a) an increase in hepatic synthesis of prebetalipoproteins, and (b) reduced elimination of prebetalipoproteins and chylomicrons from the bloodstream, due to diminished activity of lipoprotein lipase in insulin deficiency. The role of heredity has been put in doubt by the observation that diabetes and hypertriglyceridemia are not transmitted by the same genetic factor. The shortterm and longterm implications of diabetic hyperlipemia are discussed, together with the treatment.
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PMID:[Hyperlipemia and diabetes]. 18 65

The activity of two triglyceride lipases was determined by an immunochemical method in the postheparin plasma of 60 diabetic patients and of 47 age- and sex-matched nondiabetic control subjects. The results were related to the type of diabetes, to plasma triglyceride and insulin concentrations, to removal of exogenous fat from the blood, and to turnover of VLDL-triglycerides . The mean postheparin plasma lipoprotein lipase (LPL) activity was decreased by 44 per cent (p less than 0.001) in patients with untreated ketotic diabetes and by 20 per cent (p less than 0.01) in patients with untreated mild to moderate nonketotic early-onset diabetes. Insulin treatment of ketotic diabetes resulted in a rapid increase in the activity of LPL and decrease in serum triglycerdie level, whereas sulfonylurea treatment of non-insulin-requiring diabetics did not significantly influence the enzyme activity. In insulin-treated chronic diabetics the average postheparin plasma LPL activity was not different from that of nondiabetic controls, but some of these patients had high LPL values. In normolipidemic maturity-onset-type diabetics the LPL activity was within normal range, but in those having hypertriglyceridemia the average LPL value was decreased by an average of 26 per cent (p less than 0.01). The LPL activity showed a significant negative correlation with the logarithm of serum triglyceride concentration (r = -0.62) and a positive correlation with fractional removal of Intralipid (r = +0.64) and fractional turnover of V triglyceride (r = +0.40). The activity of LPL was correlated to basal plasma insulin concen tration in the insulin-deficient diabetes r = +0.34) but not in patients with maturity-onset-type diabetes. The hepatic lipase (HL) activity of postheparin plasma was similar in diabetes and controls, with the exception of hypertriglyceridemic maturity-onset diabetics, who had higher mean HL activity than the corresponding control group (p greater than 0.01). The activity of HL was not related to triglyceride removal but showed a significant correlation to VLDL-triglyceride production rate. On the basis of these results it seems that a deficiency of LPL accounts for a great deal of the elevation of serum triglyceride in insulin-deficient human diabetes but has a smaller role in the pathogenesis of the hypertriglyceridemia that is associated with maturity-onset diabetes. The latter abnormality is caused mainly by an increased secretion of triglycerides into the blood even though a decreased LPL may contribute to development of hyperlipemia in cases with gross elevation of serum triglycerides.
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PMID:Postheparin plasma lipoprotein lipase and hepatic lipase in diabetes mellitus. Relationship to plasma triglyceride metabolism. 18 16

Primary type V hyperlipoproteinemia was identified in two preadolescent children. The propositus (kindred N) was a 10-year-old girl with severely creamy plasma, lipemia retinalis, hypertriglyceridemia (triglyceridelevel, 6,800 mg/100 ml), and ypercholesterolemia (cholesterol level, 490 mg/100 ml). Her parents and an 8-year-old sister all had endogenous hypertriglyceridemia (type IV hyperlipoproteinemia). In kindred A, an 11-year-old boy had triglyceride levels as high as 1,100 mg/100 ml and recurrent abdominal pain. His father had type V hyperlipoproteinemia; his mother was normal. All three of his older teenage siblings had type IV hyperlipoproteinemia. The enzymatic activities of lipoprotein lipase (LPL), hepatic triglyceride lipase (HTL), and histaminase (H) were studied in postheparin plasma. The LPL level was low in the children and both parents in kindred N. LPL level in kindred A was normal, except for one child with type IV hyperlipoproteinemia. HTL level was normal to above normal in both kindreds. Most patients had a normal H level, but one parent (kindred N) had no preheparin H and very low levels of postheparin H. There was a strong correlation (r = 0.58, significant at less than 1% level) between release of LPL and H but not between HTL and H (r= 0.22). The mean (+/- 1 S.D.) levels of the enzymes were as follows: LPL, 2.8 +/- 0.7 micronmol/ml/hr in kindred N and 5.4 +/- 2.2 micronmol/ml/hr in kindred A; H, 13.4 +/- 6.8 units/ml in kindred N and 22.0 +/- 11.9 units/ml in kindred A; and HTL, 18.0 +/- 7.1 micronmol/ml/hr in kindred N and 14.9 +/- 6.3 micronmol/ml/hr in kindred A. The enzymatic activities of kindreds N and A were significantly different for LPL (P less than .001) and H (.025 less than P less than .05) but not for HTL. All but one child had at least one high insulin level, which was accompanied by hyperglycemia in two children. The hypertriglyceridemia in all but one child was ameliorated on therapeutic diets. These data suggest that the genetic basis of the hypertriglyceridemia in these two families is different and that hyperchylomicronemia in childhood is not confined to the rara type I hyperliporproteinemia.
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PMID:The clinical, biochemical, and familial presentation of type V hyperlipoproteinemia in childhood. 19 90

At present the two different mechanisms underlying the hypertriglyceridemia of diabetes are reasonably well defined. The rationale of therapy has grown from this knowledge. One form of hyperlipidemia is due to the hyperinsulinemia which results from the patient's resistance to insulin. The approach to treatment aims to overcome the insulin resistance. In most patients this is done by treating their obesity. The other form of hypertriglyceridemia results from insulin deficiency and is treated by bringing the patient's diabetes under control. There is strongly suggestive evidence that hypertriglyceridemia may be associated with a high risk of atherosclerosis. The reason for treating hypertriglyceridemia in general, and in the diabetic in particular, is to reduce this risk. However, it must be conceded that, at the moment, there is no information about the effect of lower triglyceride levels on the incidence of atherosclerosis. Hence much epidemiologic research is needed before our rationale for treatment can move from the realm of hope to the realm of definite proof. In the mean time an attack on this and the other risk factors is the best way we have to attempt to prevent the major complication of diabetes, atherosclerosis.
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PMID:Hyperlipidemia, atherosclerosis, and diabetes. 20 21

A patient with partial lipodystrophy is described in whom hypertriglyceridaemia was accompanied by marked hyperinsulinaemia. The hyperlipidaemia was due to increased plasma levels of very low density lipoprotein (VLDL). Kinetic studies, performed after injection of autologous radioiodinated VLDL, indicated that the raised VLDL levels were associated with over-production of this lipoprotein. Administration of diazoxide led to a substantial fall in serum insulin levels, accompanied by reduction in VLDL production and in serum triglyceride concentration. The possible role of insulin in inducing hyperlipidaemia by causing over-production of VLDL is discussed.
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PMID:Lipodystrophy with hyperlipidaemia: the role of insulin in very low density lipoprotein over-synthesis. 21 52

A case of diabetic lipemia is reported in a 27 year-old man admitted for acute pancreatitis. Initial investigations revealed gross hyperlipoproteinemia and ketoacidosis. Hyperlipoproteinemia was progressively corrected up to normalization in four weeks under insulin-therapy; the metabolic control of diabetes was obtained in parellel. This feature is caracteristic of "diabetic lipemia". The following sequence could be suggested: onset of diabetes, occurence of diabetic lipemia and then acute pancreatitis.
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PMID:[Acute pancreatitis during "diabetic lipemia": unusual disclosure of insulin-dependent diabetes (author's transl)]. 22 21

This paper reviews most of the clinical studies on the mode of action of halofenate, an established hypolipidemichypouricemic agent in man. In yeast cutlures and in isolated rat adipocytes, halofenate was found to inhibit the conversion of pyruvate to acetyl CoA. While pyruvate dehydrogenase was inhibited in vitro, halofenate also inhibited the activety of various other isolated enzymes. In rats maintained on halofenate in the diet (0.02-0.10%) for 2-14 days, there were 20-40% decreases in plasma cholesterol, trigly cerides, phospholipids, and free fatty acids. Inhibition of liver HMG-CoTA reductase does not appear to account for the hypocholesterolemic effect, and activation of mitochondrial alpha-glycerophosphate dehydrogenase does not explain the hypotriglyceridemic action. Kinetic measurements of the serum appearance and disappearance of triglycerides in drug-treated rats suggest that the hypotriglyceridemic activity is due to a net inhibition of hepatic triglyceride synthesis. Reduction of very low density lipoprotein (VLDL) and high density lipoprotein (HDL) levels in rats with sucrose-induced hyperlipidemia and normalization of the altered apolipoprotein profiles are in accord with the effects of halofenate on plasma triglyceride and cholesterol levels. The reduced insulin-to-glucagon ratio observed in Zucker obese hyperlipemic rats is also consistent with halofenat's hypotriglyceridemic activity. Preliminary experiments in rats on the mechanism of its hypoglycemic activity, observed in some diabetic hyperlipidemic patients, indicate that halofenate acts differently than conventional oral hypoglycemic agents. Some, but not all, of the effects of halofenate were observed with clofibrate at two to ten times higher levels.
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PMID:Studies on the mechanism of action of halofenate. 31 18

Obesity in the Zucker rat is accompanied by hyperlipemia, hyperinsulinism, insulin resistance, pancreatic hyperplasia, and islet hypertrophy. This study correlates the morphologic heterogeneity of isolated pancreatic islets with secretion of insulin and glucagon in the perifusion system. Islet size was arbitrarily defined as large (greater than 0.45 mm) or small (smaller than 0.12 mm). Protein content and volume (V = 4/3pir3) were calculated for groups and individual islets, respectively. Islets from obese rats secreted more insulin in response to glucose and aminophylline than islets from lean rats (peak 7.8 +/- 2.4 vs. 1.5 +/- 0.37 microU/islet/min, P less than 0.005). Insulin release was related directly to islet size and protein content. Small islets from lean and obese animals produced less insulin per islet than large islets (P less than 0.005). In terms of islet volume, however, large islets were inefficient insulin releasers as compared to small islets (P less than 0.005). Stimulation with Br-cAMP released glucagon from islets of lean but not from large islets of obese animals (peak 11 +/- 3.3 vs. 4.1 +/- 0.3 pg/microgram protein per minute, P less than 0.05). Arginine produced the same effect on glucagon release (P less than 0.05) as stimulation with Br-cAMP. The observed increased insulin release rates and the blunted glucagon response are related to islet size in the pancreas of the Zucker rat.
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PMID:Correlation between morphology and function in isolated islets of the Zucker rat. 37 79

Report on two patients with endogenous hypertriglyceridemia. In both patients normal serum lipid values were reached in a comparatively short time under a diet with reduced carbohydrates and calories. In one diabetic patient who needed insulin at the beginning of the treatment the disease could be controlled by dietary measures alone after a few days. Different biological half-life periods of the various serum lipid fractions explain why, under a reducing diet, the rate of decrease of lipids is variable according to the respective component. Thus, the ratio of triglycerides and cholesterol can vary in the same patient within a few days and may change his classification under different types of hyperlipidemia according to Fredrickson. It would appear that in these cases a classification based on etiological considerations is more recommendable.
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PMID:[Regression of xanthomas in endogenous hypertriglyceridemia under low carbohydrate diet]. 41 10


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