Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Men with regular physical training habits voluntarily increased their dietary fat intake from 43 to 54% of energy (E%) for four weeks. This was followed by a low-fat (29 E%), high-carbohydrate diet for another four weeks. During the high-fat diet period, the muscle lipoprotein lipase activity (LPLA) increased from 59 +/- 8 to 106 +/- 12 mU/g (mean +/- SE) (P less than 0.05). After the high-carbohydrate diet, LPLA was 57 +/- 16 mU/g, and unchanged relative to the pre-trial value. The triglyceride content in m. vastus lateralis increased from 30 +/- 4 to 47 +/- 9 mmol/kg d.w. (P less than 0.05; mean +/- SE) following the high-fat diet and to 41 +/- 8 following the high-carbohydrate diet. Neither of the diets affected the serum triglyceride and insulin concentrations, nor glucose, glycerol, beta-hydroxybutyrate, citrate and lactate levels in the blood. Nor did they alter enzyme activities in muscle used as markers for the oxidative (citrate synthase, beta-hydroxy-acyl CoA dehydrogenase) and glycolytic (glyceraldehyde phosphate dehydrogenase, lactate dehydrogenase) capacity. It is concluded that one month's adaptation to a high-fat diet results in increased muscle-LPL activity indicating a higher capacity for uptake of fatty acids from circulating serum triglycerides into the muscle cell in association with a greater capacity for triglyceride storage in the muscle. Under these conditions serum triglycerides were not decreased despite the increased muscle LPLA, and serum insulin variations could not explain the change in muscle LPLA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lipoprotein lipase activity and intramuscular triglyceride stores after long-term high-fat and high-carbohydrate diets in physically trained men. 354 51

Muscle fibre composition, fibre areas and enzyme activities were determined in muscle biopsy samples (m. vastus lateralis) from both legs of 34 clinically healthy men and 31 clinically healthy women (aged 20-70 years). No significant difference was found in any of the three variables between the right and left leg. In the whole material the mean percentage of type I fibres was significantly higher in men, whereas that of type IIA fibres was significantly higher in women (men 58% I, 27% IIA, 13% IIB, women 51% I, 32% IIA, 15% IIB). The areas of all fibre types were significantly larger in men than in women. When the subjects were divided into age groups of 20, 30, 40, 50, 60 and 70 years, respectively, the fibre composition was found to be similar at different ages in both men and women, but changes in fibre areas were observed. The 70-year-old men and women showed significantly reduced areas of both type I and II fibres compared with the 60-year-olds. Only minor changes were seen in enzyme activities in relation to age. Men of the youngest age group had significantly higher levels of citrate synthase activity than those of the older age groups. Similar findings were seen for women except for the 60-year-olds, who had as high activity levels of citrate synthase as the 20-year-olds.
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PMID:Histochemical and metabolic characteristics of human skeletal muscle in relation to age. 395 98

Men with chronic heart failure (CHF) have alterations in their skeletal muscle that are partially responsible for a decreased exercise tolerance. The purpose of this study was to investigate whether skeletal muscle alterations in women with CHF are similar to those observed in men and if these alterations are related to exercise intolerance. Twenty-five men and thirteen women with CHF performed a maximal exercise test for evaluation of peak oxygen consumption (VO(2)) and resting left ventricular ejection fraction, after which a biopsy of the vastus lateralis was performed. Twenty-one normal subjects (11 women, 10 men) were also studied. The relationship between muscle markers and peak VO(2) was consistent for CHF men and women. When controlling for gender, analysis showed that oxidative enzymes and capillary density are the best predictors of peak VO(2.) These results indicate that aerobically matched CHF men and women have no differences in skeletal muscle biochemistry and histology. However, when CHF groups were separated by peak exercise capacity of 4.5 metabolic equivalents (METs), CHF men with peak VO(2) >4.5 METs had increased citrate synthase and 3-hydroxyacyl-CoA dehydrogenase compared with CHF men with peak VO(2) <4.5 METs. CHF men with a lower peak VO(2) had increased capillary density compared with men with higher peak VO(2). These observations were not reproduced in CHF women. This suggests that differences may exist in how skeletal muscle adapts to decreasing peak VO(2) in patients with CHF.
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PMID:Differences in skeletal muscle between men and women with chronic heart failure. 1113 20