Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.34 (lipoprotein lipase)
 7,025 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the present study, fetuses were hypophysectomized (hypox) in utero on d 72 to 74 of gestation with an electrical cauterizing needle. One to six successfully hypox fetuses were removed on d 110 of gestation from each of five gilts. Subcutaneous adipose tissue samples and semitendinosus muscles were obtained from the hypox fetuses and an equal number of control fetuses. Body weights of control fetuses (n = 15; mean +/- SE, 1,195 +/- 33 g) were similar to weights of hypox fetuses (n = 15; 1,179 +/- 67 g). Fat cell size in the middle subcutaneous layer of adipose tissue was increased in hypox fetuses (P less than .01) compared with control fetuses. The number of obvious fat cell clusters (outer layer) in lipid stained sections was reduced (P less than .01) by 50% in hypox fetuses. Histochemical reactions for glucose-6-phosphate dehydrogenase, esterase and lipoprotein lipase (LPL) activities in middle layer cell clusters were considerably enhanced in sections from hypox fetuses compared with sections from controls. Quantitative analysis of percent light transmittance (Zeiss photometer) through LPL-stained cell clusters indicated an increase (P less than .001) in LPL staining in sections from hypox fetuses when compared with sections from control fetuses. Transverse muscle sections (cryostat) from hypox fetuses failed to show normal patterns (as seen in control muscles) of reactions for acid ATPase, malate dehydrogenase (NAD-dependent), NADH-TR and alpha-glycerol phosphate dehydrogenase (without NAD). The number of muscle fibers that were stained for these enzymes was greatly reduced in hypox fetuses compared with control fetuses. The number of lipid positive fibers was also reduced in hypox fetuses compared with control fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Differentiation of adipose tissue and muscle in hypophysectomized pig fetuses. 357 Oct 30

Mammary metabolism was studied in 4 normal lactating goats (group N) and in 4 non-pregnant goats induced to lactate by hormonal treatment (group 1). Tissue was sampled by biopsy after 3, 9 and 18 weeks of lactation. Although milk potential was the same in both groups, group 1 produced 45% less milk than group N. The RNA-DNA ratio, activities of lipoprotein lipase (LPL), glucose-6-phosphate dehydrogenase and acetyl-CoA carboxylase, and the beta-casein % of in vitro protein synthesis were not significantly lower in the 1 than in the N goat mammary tissue. This suggests that differences in mammary cell hyperplasia during hormonal treatment, and not potential metabolic activities, partially accounted for the difference in milk yield levels. Milk composition was comparable in the two groups. However, milk fat in group N had a higher long-chain fatty acid content (stearic and oleic acids) during the first month of lactation due to the higher mobilization of body lipids in high-yielding animals. Another qualitative difference was the delayed increase in milk LPL secretion during the first 3 months of lactation in induced goats.
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PMID:Mammary metabolism in the goat during normal or hormonally-induced lactation. 372 70

Samples of perirenal adipose tissue were obtained from four fetuses from each of seven crossbred gilts at each of three stages of gestation: 70, 90, and 110 days. Samples were routinely prepared for histochemistry and histology. At each age, the largest fat cell clusters were consistently located near points where large blood vessels entered the loose connective tissue. Cell-cluster size decreased with distance from the entry points of large blood vessels. Fat cells proximal to entry points of large arterioles and fat cells distal to entry points of large arterioles were the same size. Enzyme cytochemistry disclosed that reactions for glucose-6-phosphate dehydrogenase (G6PDH), lipoprotein lipase (LPL) and NADH-TR enzymes were reduced in distal (relative to entry points of large arterioles) adipocytes compared with proximal adipocytes. Reactions for succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH) in adipocytes were not influenced by location within the tissue. Small fat cell clusters with sparse capillary beds surround arterioles in distal areas of sections from fetuses at 70, 90, and 110 days of gestation. In the proximal areas of sections from 110-day-old fetuses, arterioles were surrounded by large fat cell clusters with dense capillary beds. These characteristics serve to distinguish perirenal depots from subcutaneous depots in the fetus.
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PMID:Structural and histochemical aspects of perirenal adipose tissue in fetal pigs: relationships between stromal-vascular characteristics and fat cell concentration and enzyme activity. 380 82

The effect of isatin on serum lipid concentrations, the activity of lipoprotein lipase, the activity of lipogenic enzymes and the oxidation rate of fatty acids of female Wistar rats were investigated. A decrease of the triglyceride concentrations could be observed after one week of treatment of the group of sucrose-rich alimented animals, after two weeks this was also the case with the group fed with standard food. There were no changes in the cholesterol concentrations. Post-heparin lipolytic activity was not influenced. The liver enzymes malic enzyme, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase showed a remarkable increase in activity. The simultaneous rise of the oxidation rate of 14C-palmitate in the liver was measured. On the basis of the present findings the accelerated degradation rate could be responsible for the hypolipemic effect of the substance. The possible participation of the carnitine shuttle in the lipid-lowering action is discussed on the basis of changed concentrations of total carnitine, free carnitine and acylcarnitine in pooled serum samples after treatment with isatin.
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PMID:The response of some intravascular and intracellular lipid parameters of the rat after treatment with isatin. 400 19

It has been shown that the same modifications on the composition of brown adipose tissue (BAT) which are normally induced following cold stimulation are also observed in hypophysectomized rats acclimated either at 28 degrees C or 15 degrees C. To test the possibility of BAT stimulation in hypophysectomized rats, we have determined some enzymatic activities known to modulate the energy supply to that organ. Seven week old Long-Evans rats were hypophysectomized. Three weeks later, they were exposed to either 28 degrees C or 15 degrees C ambient temperature for five or six weeks. Hypophysectomized rats were compared to age matched or weight matched controls. Total lipoprotein lipase activity (LPL) (triglyceride uptake) was enhanced in BAT of 28 degrees C hypophysectomized rats compared to controls. Cold acclimation led to a large increased activity. Total LPL activity was comparable in BAT of hypophysectomized and control rats. Total malic enzyme and glucose-6-phosphate dehydrogenase activities (in situ lipogenesis) were doubled in BAT of 28 degrees C hypophysectomized compared to controls. A large enhancement was observed in BAT of either 15 degrees C control or 15 degrees C hypophysectomized rats. Among the studied organs (liver, white adipose tissue, heart, BAT) hypophysectomy promotes the three enzyme activities only in BAT. These variations were discussed with relation to the effect of hypophysectomy on brown adipose tissue at 15 degrees C and 28 degrees C.
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PMID:Effect of temperature on lipoprotein lipase and lipogenic enzyme activities in brown adipose tissue of hypophysectomized rats. 400 67

Dehydroepiandrosterone (DHEA) is a known noncompetitive inhibitor of glucose-6-phosphate dehydrogenase (G6PD). In the present investigation, the effects of chronic DHEA treatment on G6PD and several other enzymes involved in lipid metabolism were examined in lean and obese Zucker rats. Significant decreases in body weight were found in DHEA-treated rats in comparison with nontreated rats. In lean rats, DHEA treatment did not decrease either liver or adipose tissue G6PD and fatty acid synthetase activity, but malic enzyme activity was increased. In obese rats, decreased liver and adipose tissue G6PD and fatty acid synthetase activities were found. Malic enzyme activity in liver of obese DHEA rats was increased but not in adipose tissue. Adipose tissue lipoprotein lipase activity was decreased in both lean and obese DHEA rats. Serum insulin in obese DHEA rats was also decreased compared with control obese rats. These results indicate that the inhibition of G6PD may not be the mechanism of action of the antiobesity effect of DHEA. However, the metabolic effects of DHEA seen in obese rats may contribute to its antiobesity action.
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PMID:Metabolic alterations after dehydroepiandrosterone treatment in Zucker rats. 623 14

Although human milk generally contains higher levels of enzymes than bovine milk, little definitive information is available concerning their role or significance. The enzyme levels in human milk as compared to bovine milk and levels in human colostrum versus normal milk are summarized. The few most widely studied human milk enzymes are discussed in more detail. Evidence is presented to support the views that 1) lipoprotein lipase and ribonuclease are probably spilled into the milk from the blood; 2) lysozyme is spilled from the secretory epithelial cells; 3) lactate and malate dehydrogenases, glucose-6-phosphate dehydrogenase, and lactose synthetase are synthesized in the mammary gland in response to hormonal stimuli; and 4) bile salt stimulated lipase, diastase, protease, and lysozyme are present in sufficient quantities to aid infants in growth and nutrition. Consideration must be given to standardizing the various enzyme assay procedures and activity units so that meaningful comparisons between various studies could be made.
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PMID:Role and significance of enzymes in human milk. 740 88

Factors associated with the development of obesity were compared among obese (fa/fa), heterozygous (Fa/fa) lean and homozygous (Fa/Fa) lean Zucker rats at 17 d of age. Inguinal pad weight, pad-to-body weight ratio and fat cell size were highest in obese pups (fa/fa > Fa/fa > Fa/Fa). Hepatic glucose-6-phosphate dehydrogenase activity was greater in fa/fa than in Fa/Fa pups; 6-phosphogluconate dehydrogenase activity was higher in fa/fa and Fa/fa pups than in Fa/Fa pups, and fatty acid synthetase was greater in fa/fa compared with lean pups (Fa/fa = Fa/Fa). The fa/fa pups had greater adipose tissue glucose-6-phosphate dehydrogenase, malic enzyme and fatty acid synthetase activities than lean pups, which did not differ from one another (Fa/fa = Fa/Fa), whereas 6-phosphogluconate dehydrogenase and lipoprotein lipase activities were highest in obese pups, intermediate in heterozygotes and lowest in homozygous lean rats (fa/fa > Fa/fa > Fa/Fa). Glucose conversion to carbon dioxide and fatty acids in isolated adipocytes was highest in obese pups (fa/fa > Fa/fa > Fa/Fa). Glyceride-glycerol production was greater in Fa/Fa than in fa/fa or Fa/fa pups. These findings indicate that many characteristics of obesity are evident in preobese Zucker rats, and for some factors the presence of the "fa" gene in lean rats results in intermediate measurements relative to the two homozygous genotypes.
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PMID:Metabolic measurements among homozygous (fa/fa) obese, heterozygous (Fa/fa) lean and homozygous (Fa/Fa) lean Zucker rat pups at 17 days of age. 791 18

The possibility that risk of a atherosclerosis complication increases with oral contraceptive use was examined by studying the effect of oral pill containing 0.067 mg menstranol and 0.667 mg ehtynodiol diacetate/kg body weight on the metabolism of lipids in female rats fed a hypercholesterolemic diet for three months. Experimental group clearly exhibited higher levels of triglycerides and cholesterol in plasma and tissues, increase in aorta observed to be two folds. Increased hepatic cholesterogenesis was noted with treatment of oral contraceptive as indicated by higher activity of HMG-CoA reductase. Activity of lipoprotein lipase of extrahepatic tissue was depressed in experimental group. Activity of plasma LCAT, an enzyme involved in the transport of cholesterol from tissues, was also lower with treatment of oral contraceptive. However, activity of malic enzyme and glucose-6-phosphate dehydrogenase enhanced considerably with administration of oral pill. The increase in plasma and aortic cholesterol levels, increase in LDL+VLDL cholesterol and considerable decrease in HDL cholesterol in animals treated with oral contraceptives and fed with atherogenic diet, indicates that prolonged administration of oral pill may predispose towards atherosclerosis.
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PMID:Role of oral contraceptive in atherosclerosis. 792 21

An in vitro system was used to study the regulation of lipoprotein lipase (LPL) activity in bovine adipose tissue. The utilization of two energetic and lipogenic substrates, acetate and glucose, and the activity of glucose-6-phosphate dehydrogenase (G6PDH), an enzyme involved in de novo lipogenesis, were also studied. Nine nonlactating, nonpregnant Holstein cows were given limited amounts of feed for 10 d, then they were overfed for 3 to 5 wk. Samples of perirenal adipose tissue were incubated for 24 or 48 h. Insulin (2 mU/mL) increased (P < .001) daily glucose and acetate utilization and attenuated (P < .001) the loss of G6PDH activity detected after 1 or 2 d of incubation. Dexamethasone (DEX, 10 nM) added to the insulin-supplemented medium decreased (P < .02) glucose utilization, but it did not change acetate utilization or G6PDH activity. A higher concentration of DEX (100 nM) potentiated (P < .004) the ability of insulin to attenuate the decrease in G6PDH activity without changing substrate utilization. Under basal conditions, LPL activity was decreased by approximately 66% after 2 d of incubation. The decline in LPL activity was attenuated by insulin addition (P < .02) and was further attenuated (P < .004) by 100 nM of DEX. The addition of 10% fetal bovine serum alone to the medium had no effect on LPL activity, and fetal bovine serum decreased this activity when it was added to the insulin-supplemented medium.
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PMID:Lipoprotein lipase and metabolic activities in incubated bovine adipose tissue explants: effects of insulin, dexamethasone, and fetal bovine serum. 813 88


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