Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lipoprotein lipase is an enzyme in adipose tissue that hydrolyzes circulating triglycerides and thereby generates the fatty acids used in the synthesis of triglyceride in fat cells. To determine whether the activity and expression of lipoprotein lipase are affected by weight loss, we studied lipoprotein lipase in the adipose tissue of nine very obese subjects before and after a program of weight reduction. The subjects' mean (+/- SEM) initial weight was 136 +/- 7.3 kg, and the body-mass index (weight in kilograms divided by the square of the height in meters) ranged from 33.3 to 52.8 (mean, 43.0 +/- 2.5). Biopsies of adipose tissue were performed before weight loss and after it, when weight had been stable for three months. The weight reduction was achieved by a very-low-calorie diet (mean weight loss, 42.5 +/- 6.8 kg). After weight loss, the level of heparin-releasable lipoprotein lipase activity increased in all patients, from 3.8 +/- 1.1 to 7.1 +/- 1.6 neq of free fatty acid released per minute per 10(6) cells (P less than 0.05). In addition, the amount of lipoprotein lipase immunoreactive protein increased from 6.3 +/- 1.7 to 24.4 +/- 6.9 ng per 10(6) cells (P less than 0.05), and there was also an increase in the level of lipoprotein lipase messenger RNA as measured by Northern blotting. There was a strongly positive correlation between the initial body-mass index and the magnitude of the increase in lipoprotein lipase activity (r = 0.80, P less than 0.01) and immunoreactive protein (r = 0.92, P less than 0.01). We conclude that weight loss in very obese subjects leads to the increased activity and expression of lipoprotein lipase, thereby potentially enhancing lipid storage and making further weight loss more difficult.
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PMID:The effects of weight loss on the activity and expression of adipose-tissue lipoprotein lipase in very obese humans. 232 65

To study postheparin plasma lipase activities in nonfed newborn infants immediately after birth and to investigate the possible influence of fetal hyperinsulinemia on lipoprotein lipase activity, we measured lipoprotein and hepatic lipase activities in 55 macrosomic newborn infants: group I consisted of 21 infants born to mothers with insulin-dependent diabetes. The infants were hyperinsulinemic at birth and had hypoglycemia and poor lipolysis at the age of 2 h. Group II consisted of 18 infants born to mothers with gestational diabetes. Group III consisted of 16 large-for-date infants born to nondiabetic mothers. The mean postheparin plasma lipoprotein lipase activities at 2 h of age were similar (mean 36 mumol free fatty acids/ml/h; SEM 15) in groups I-III. Lipoprotein lipase activity correlated negatively with cord-serum triglycerides (range 0.13-1.2 mmol/liter) but did not correlate with serum insulin (range 5.4-524 microU/ml) or C-peptide (range 0.6-21.0 micrograms/liter). Hepatic lipase activity was somewhat higher in group I (mean 68 mumol free fatty acids/ml/h; SEM 23) than in groups II and III (mean 55 mumol free fatty acids/ml/h; SEM 14). Hemoglobin Alc was the only important factor explaining the difference in hepatic lipase activities between groups. Lipoproteins and apolipoproteins A-I, A-II, and B were similar in all three groups. We conclude that in large-for-date infants lipoprotein lipase is active at birth without exogenous fat induction, and that these infants are capable of hydrolyzing fat, their main source of energy, immediately after birth. In addition, we conclude that postheparin plasma lipoprotein lipase activity is not affected by fetal hyperinsulinemia.
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PMID:Postheparin plasma lipoprotein and hepatic lipase activities in hyperinsulinemic infants of diabetic mothers and in large-for-date infants at birth. 308 29

Lipoprotein lipase was measured in gluteal adipose tissue from nine obese (90.6 +/- 2.7 kg) women fasting and after the intravenous infusion of insulin and glucose before, immediately after, and 3 mo subsequent to a 14.0 +/- 1.8% (mean +/- SEM) weight reduction. Fasting adipose tissue lipoprotein lipase activity (ATLPL) decreased from 5.3 to 2.3 nEq FFA/10(6) cells per min (P less than 0.02) immediately after weight reduction, yet after weight maintenance, higher levels were again found (6.1 nEq FFA/10(6) cells per min). Although responsiveness of ATLPL to 40 mU/m2 per min of insulin infusion over 6 h was absent before weight loss, increases were seen immediately after weight loss (delta 0.8, P = 0.05) and more so (delta 7.7, P less than 0.01) after 3 mo. Moreover, whereas before weight loss the ATLPL response to ingested mixed meals (delta 0.9) was minimal, in the maintained reduced-obese state a marked increase was seen (delta 12.6, P = 0.02). Thus, because ATLPL is important to lipid filling in adipose tissue, the maintenance of high levels of fasting ATLPL and the increase in enzyme responsiveness in the reduced-obese state could play an important role in the resumption of the obese state, which so commonly follows weight reduction.
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PMID:Weight reduction increases adipose tissue lipoprotein lipase responsiveness in obese women. 330 61

Twenty six preterm infants were studied at the age of 2, 7, and 26 days. The activities of lipoprotein and hepatic lipase in plasma taken 15 minutes after a heparin bolus of 100 IU/kg had been given and the concentrations of carnitine in serum and urine were measured. The mean gestational age was 31 weeks (range 26-35 weeks) and birth weight 1580 g (range 840-2280 g). Thirteen infants weighed under 1500 g at birth (very low birth weight), 20 were of appropriate weight for gestational age and six were small for gestational age. Lipoprotein lipase activity was higher in the preterm infants of appropriate weight than in the infants of very low birth weight and those who were small for gestational age. At the age of 2 or 7 days the activity of lipoprotein lipase in the preterm infants (mean (SEM) 46.2 (4.3) mumol free fatty acid/ml/hour) was, however, higher than in term infants and adults. Multivariate regression analyses showed that weight and relative birth weight together explained 58% of the variance of lipoprotein lipase activity but only 3% of the variance of hepatic lipase activity. Serum carnitine concentration was lower in the preterm infants than in term infants. Urinary excretion of carnitine increased progressively with age but was independent of serum concentration and carnitine intake. Urinary excretion of total carnitine was significantly greater in the infants who were small for gestational age (mean (SEM) 754 (203) nmol/mg of creatinine, n = 6) than in the infants of appropriate weight (161 (22.0) nmol/mg of creatinine, n = 12) but acyl/free carnitine ratio was smaller in the infants who were small for gestational age than in infants of appropriate weight (0.56 v 5.5). The results indicate that the slow elimination of fat from the circulation in preterm infants less mature than 32 weeks of gestation can hardly be explained by low lipoprotein lipase activity.
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PMID:Lipoprotein lipase, hepatic lipase, and carnitine in premature infants. 334 61

To study postheparin plasma lipase activities in nonfed newborn infants immediately after birth and to investigate the possible influence of fetal hyperinsulinemia on lipoprotein lipase activity, we measured lipoprotein and hepatic lipase activities in 55 macrosomic newborn infants: group I consisted of 21 infants born to mothers with insulin-dependent diabetes. The infants were hyperinsulinemic at birth and had hypoglycemia and poor lipolysis at the age of 2 h. Group II consisted of 18 infants born to mothers with gestational diabetes. Group III consisted of 16 large-for-date infants born to nondiabetic mothers. The mean postheparin plasma lipoprotein lipase activities at 2 h of age were similar (mean 36 mumol free fatty acids/ml/h; SEM 15) in groups I-III. Lipoprotein lipase activity correlated negatively with cord-serum triglycerides (range 0.13-1.2 mmol/liter) but did not correlate with serum insulin (range 5.4-524 microU/ml) or C-peptide (range 0.6-21.0 micrograms/liter). Hepatic lipase activity was somewhat higher in group I (mean 68 mumol free fatty acids/ml/h; SEM 23) than in groups II and III (mean 55 mumol free fatty acids/ml/h; SEM 14). Hemoglobin Alc was the only important factor explaining the difference in hepatic lipase activities between groups. Lipoproteins and apolipoproteins A-I, A-II, and B were similar in all three groups. We conclude that in large-for-date infants lipoprotein lipase is active at birth without exogenous fat induction, and that these infants are capable of hydrolyzing fat, their main source of energy, immediately after birth. In addition, we conclude that postheparin plasma lipoprotein lipase activity is not affected by fetal hyperinsulinemia.
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PMID:Postheparin plasma lipoprotein and hepatic lipase activities in hyperinsulinemic infants of diabetic mothers and in large-for-date infants at birth. 352 12

The cellular regulation of adipose tissue lipoprotein lipase by insulin was investigated using cultured isolated rat adipocytes. Evidence for sustained cell viability over 3 days included stability of specific [125I]insulin binding and adipocyte number. Lipoprotein lipase was measured in three functional compartments: 1) enzyme activity secreted into the culture medium, 2) activity releasable from cell suspensions by heparin, and 3) activity extractable from cells (after maximal heparin release) in deoxycholate and detergent. One day after preparation, these activities stabilized and were 1.3 +/- 0.2, 1.4 +/- 0.2, and 7.7 +/- 0.9 neq/10(6) cells X min, respectively (n = 24, mean +/- SEM). Insulin, added the day after preparation, produced a dose-dependent (1-400 ng/ml) increase in lipoprotein lipase releasable from cells by heparin at 2, 4, and 24 h. Insulin also increased intracellular enzyme measured as deoxycholate-detergent-solubilized activity extracted from previously heparin-released cells. However, insulin-mediated increases in culture medium enzyme only occurred subsequent to cellular effects. All insulin-mediated effects were prevented by cycloheximide (1 microgram/ml). Thus, insulin increased two cellular pools of adipocyte lipoprotein lipase in a dose-dependent manner, but had no direct effect on enzyme secretion. Overall, cultured isolated rat adipocytes appear to be a valuable system for the study of lipoprotein lipase regulation at the level of the adipocyte.
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PMID:Insulin regulation of lipoprotein lipase in cultured isolated rat adipocytes. 637 Jun 64

Lipoprotein lipase (LPL) hydrolyzes lipoprotein triglyceride into nonesterified fatty acids, which are then reesterified and stored in adipose tissue. Previous studies have demonstrated increases in LPL in response to insulin-like growth factor I and GH when added in vitro. This study examined the effects of acromegaly treatment on adipose tissue LPL. Ten patients with clinically active acromegaly were recruited. A fasting adipose tissue biopsy was performed both before and 3 months after treatment with octreotide (8 patients) or surgery plus octreotide (2 patients). With treatment, mean baseline insulin-like growth factor I levels fell from 6.41 to 3.98 U/mL (normal, < 2.2 U/mL; P < 0.05), and serum glycohemoglobin fell from 8.6 to 7.2 (normal, < 6.8). Adipose LPL was measured in the heparin-released fraction as well as the cellular fraction extracted with nonionic detergent (EXT). After treatment of acromegaly, there was no change in heparin-released fraction LPL activity or immunoreactive mass. However, there was an increase in EXT activity from 0.73 +/- 0.33 to 1.83 +/- 0.58 nEq/min.10(6) cells (mean +/- SEM; P < 0.05) and an increase in EXT mass from 4.1 +/- 0.89 to 11.4 +/- 2.0 ng/10(6) cells (P < 0.05). There was no change in LPL messenger ribonucleic acid levels with treatment, determined using both quantitative polymerase chain reaction and Northern blotting. Thus, treatment of acromegaly resulted in an increase in the intracellular level of the LPL protein, with no change in messenger ribonucleic acid levels, suggesting posttranscriptional regulation of LPL. These changes in LPL may be due to improved insulin sensitivity, or to other changes associated with acromegaly treatment.
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PMID:Effects of acromegaly treatment and growth hormone on adipose tissue lipoprotein lipase. 759 31

1. Lipoprotein lipase (LPL) was isolated from five rat tissues: white adipose, skeletal muscle, cardiac muscle, mammary gland and lung. 2. Specific activity of the preparations varied from 75 U/mg for skeletal muscle and 720 U/mg for adipose. 3. The preparations were further analysed using SDS-PAGE and a single component identified. The mol. wt of 61,000 Da of this component was consistent for all five of the tissue sources. 4. Significant differences in the values of the isoelectric points of the enzyme species were revealed. The values varied from 7.23 (SEM 0.022) for cardiac and lung to 7.51 (SEM 0.037) for mammary. 5. Two-dimensional electrophoresis, using isoelectric focusing in the first dimension and SDS-PAGE in the second revealed differences in the patterns of stained material derived from the five tissue sources.
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PMID:Purification and characterization of lipoprotein lipase from the white adipose, skeletal muscle, cardiac muscle, mammary gland and lung tissues of the rat. 822 60