HDL2 and HDL3 cholesterol in hepatic cirrhosis

In order to further investigate plasma lipoproteins abnormalities secondary to serious liver damage, we studied plasma lipids and lipoproteins, and in particular HDL subfractions (HDL2, HDL3), in 12 patients with cirrhosis of the liver and in 12 sex, age and weight matched healthy volunteers. Enzymatic methods were used to determine total cholesterol and triglycerides, while the extractive method of Abell et al. was used for the determination of HDL-cholesterol levels after LDL and VLDL precipitation with polyanions (MnCl2 and Na-heparin) and of HDL3-cholesterol values after HDL2 precipitation with dextran-sulphate 15,000 m.w. Total cholesterol and HDL-cholesterol levels were significantly lower in cirrhotic patients compared to normal subjects. We must emphasize that only HDL3-cholesterol was decreased in cirrhotics, whereas HDL2-cholesterol values were normal or high. We suggest that a diminished activity of hepatic triglyceride lipase might account for the decrease in HDL3-cholesterol in liver cirrhosis.     

Metabolic profiles and lipoprotein lipid concentrations in non-obese and obese patients with polycystic ovarian disease

Clinical parameters, androgen status and lipoprotein lipid profiles were assessed in 10 non-obese and 10 obese patients with polycystic ovarian disease (PCOD) and reference subjects matched for age, height and weight. Both obese and non-obese women with PCOD had significantly higher androgen levels when compared to the reference groups. When comparison of lipoprotein lipid profiles were made between groups, non-obese women with PCOD had significantly higher total cholesterol, triglycerides and LDL-cholesterol levels than non-obese reference subjects. Obese PCOD women manifested significantly higher total cholesterol, LDL-cholesterol, cholesterol/HDL, and LDL/HDL values than did obese reference subjects. Correlations between serum androgens and lipoprotein lipid concentrations in PCOD and normal women were unhelpful. Both non-obese and obese patients with PCOD had significantly higher systolic and diastolic blood pressures (BPs) than the reference groups. Thus, both non-obese and obese women with PCOD manifest hyperandrogenaemia which may result in a male pattern of lipoprotein lipid concentrations.     

Variability in the response of different male subjects to the effect of marathon running on the increase in plasma high density lipoprotein

The acute effects of running a 42.2 km marathon race on the concentration and composition of the plasma lipoproteins were studied in 56 men of varying fitness, training experience, age and physical characteristics. There was no change in the mean concentration of total serum cholesterol, but a 10.9% increase (P less than 0.001) in the mean concentrations of high-density lipoprotein cholesterol (HDL-TC), representing an 11.1% increase (P less than 0.001) in the cholesteryl ester (CE) and 9.9% increase (P less than 0.001) in the unesterified cholesterol (UC) moieties of HDL. The ratio of total serum cholesterol to HDL-TC decreased significantly (P less than 0.001) during the exercise. Changes in lipoprotein concentrations during the marathon varied considerably between individual subjects, with a small proportion of subjects exhibiting relatively large increases or decreases in HDL-TC, HDL-CE and HDL-UC. Small sub-populations of runners were identified who showed abnormally large decreases in HDL-UC and abnormally small increases in HDL-CE relative to HDL-UC. A correlation (P less than 0.05) was found between the average weekly mileage of training and the increase in HDL-TC, whilst faster runners (finishing time less than 3 h; n = 13) had a significantly greater (P less than 0.02) increase in HDL-TC than slower runners (greater than 4 h; n = 14).(ABSTRACT TRUNCATED AT 250 WORDS)     

Elevation of red cell sodium-lithium countertransport in hyperlipidemias

Red cell Na-Li countertransport was measured in 78 normal subjects, 64 patients with essential hypertension, and 67 patients with hyperlipidemias. Both hypertensive and hyperlipidemic patients had elevated Na-Li countertransport compared to normal controls (p less than 0.001). Subjects with hyperlipidemia and hypertension had higher countertransport (p less than 0.02) than patients with only hyperlipidemia. Normotensive hyperlipidemic subjects had higher countertransport than normotensive and normolipidemic controls (p less than 0.02). This suggest that hypertension and high plasma lipids can influence independently the Na-Li countertransport. In another group of 52 normotensive subjects, Na-Li countertransport was positively correlated with serum total and free (unesterified) cholesterol, phospholipids and triglycerides. No correlations were found with HDL-cholesterol or HDL-phospholipids. A very high positive correlation was found between Na-Li countertransport and plasma acetylcholinesterase (p less than 0.005). These findings suggest that plasma lipids, probably through membrane lipids, can affect the maximal rate of the Na-Li exchange in red cells. The relationship between plasma or membrane lipids and cation transport should be further studied in erythrocytes and other cells.     

Improving Assessment of Lipoprotein Profile in Type 1 Diabetes by 1H NMR Spectroscopy

Patients with type 1 diabetes (T1D) present increased risk of cardiovascular disease (CVD). The aim of this study is to improve the assessment of lipoprotein profile in patients with T1D by using a robust developed method 1H nuclear magnetic resonance spectroscopy (1H NMR), for further correlation with clinical factors associated to CVD. Thirty patients with T1D and 30 non-diabetes control (CT) subjects, matched for gender, age, body composition (DXA, BMI, waist/hip ratio), regular physical activity levels and cardiorespiratory capacity (VO_2peak), were analyzed. Dietary records and routine lipids were assessed. Serum lipoprotein particle subfractions, particle sizes, and cholesterol and triglycerides subfractions were analyzed by 1H NMR. It was evidenced that subjects with T1D presented lower concentrations of small LDL cholesterol, medium VLDL particles, large VLDL triglycerides, and total triglycerides as compared to CT subjects. Women with T1D presented a positive association with HDL size (p<0.005; R = 0.601) and large HDL triglycerides (p<0.005; R = 0.534) and negative (p<0.005; R = -0.586) to small HDL triglycerides. Body fat composition represented an important factor independently of normal BMI, with large LDL particles presenting a positive correlation to total body fat (p<0.005; R = 0.505), and total LDL cholesterol and small LDL cholesterol a positive correlation (p<0.005; R = 0.502 and R = 0.552, respectively) to abdominal fat in T1D subjects; meanwhile, in CT subjects, body fat composition was mainly associated to HDL subclasses. VO_2peak was negatively associated (p<0.005; R = -0.520) to large LDL-particles only in the group of patients with T1D. In conclusion, patients with T1D with adequate glycemic control and BMI and without chronic complications presented a more favourable lipoprotein profile as compared to control counterparts. In addition, slight alterations in BMI and/or body fat composition showed to be relevant to provoking alterations in lipoproteins profiles. Finally, body fat composition appears to be a determinant for cardioprotector lipoprotein profile.     

Long Distance Runners Present Upregulated Sweating Responses than Sedentary Counterparts

Relatively few studies have investigated peripheral sweating mechanisms of long-distance runners. The aim of this study was to compare peripheral sweating mechanisms in male long-distance runners, and sedentary counterparts. Thirty six subjects, including 20 sedentary controls and 16 long-distance runners (with 7–12 years of athletic training, average 9.2±2.1 years) were observed. Quantitative sudomotor axon reflex testing (QSART) with iontophoresis (2 mA for 5 min) and 10% acetylcholine (ACh) were performed to determine axon reflex-mediated and directly activated (DIR, muscarinic receptor) sweating. Sweat onset time, sweat rate, number of activated sweat glands, sweat output per gland and skin temperature were measured at rest while maximum oxygen uptake (VO₂max) were measured during maximal cycling. Sweat rate, activated sweat glands, sweat output per gland, skin temperature and VO₂max were significantly higher in the trained runners than in the sedentary controls. Sweat onset time was significantly shorter for the runners. In the group of long-distance runners, significant correlations were found between VO₂max and sweat onset time (r² = 0.543, P<0.01, n = 16), DIR sweat rate (r² = 0.584, P<0.001, n = 16), sweat output per gland (r² = 0.539, P<0.01, n = 16). There was no correlation between VO₂max and activated sweat glands. These findings suggest that habitual long-distance running results in upregulation of the peripheral sweating mechanisms in humans. Additional research is needed to determine the molecular mechanism underlying these changes. These findings complement the existing sweating data in long-distance runners.     

Increase of Classic and Nonclassic Cardiovascular Risk Factors in Patients with Acromegaly

ObjectiveTo evaluate the prevalence of classic and nonclassic cardiovascular risk factors in patients with acromegaly.MethodsSixty-two patients with acromegaly (50 with active disease and 12 with controlled acromegaly) and 36 healthy persons (the control group) underwent measurement of lipids, fasting plasma glucose, homeostasis model assessment of insulin resistance (HOMA-IR) index, Lp(a), high-sensitivity C-reactive protein (hsCRP), homocysteine, and variables primarily related to thrombogenesis (fibrinogen, antithrombin III, protein C, and protein S).ResultsIn comparison with control subjects, patients with active acromegaly had significantly higher mean values of fasting plasma glucose, total cholesterol, low-density lipoprotein cholesterol, very-low-density lipoprotein (VLDL) cholesterol, triglycerides, Lp(a), HOMA-IR, and fibrinogen as well as lower mean levels of high-density lipoprotein cholesterol and protein S. In both groups, homocysteine, antithrombin III, protein C, and hsCRP levels were similar. Moreover, patients with active acromegaly, in comparison with those who had controlled acromegaly, presented with significantly higher values of fasting plasma glucose, HOMA-IR, triglycerides, VLDL cholesterol, Lp(a), and fibrinogen, whereas hsCRP and protein S were significantly lower. Finally, low levels of high-density lipoprotein cholesterol and protein S as well as elevated values of VLDL cholesterol, triglycerides, HOMA-IR, and fasting plasma glucose were more prevalent in patients with active acromegaly than in the other groups.ConclusionOur findings demonstrate that, in comparison with control subjects and patients with controlled acromegaly, patients with active acromegaly had a higher frequency of classic and nonclassic cardiovascular risk factors. These findings are potentially very important because acromegaly is associated with a 2- to 3-fold increase in mortality rate, predominantly related to cardiovascular disease. (Endocr Pract. 2007;13:363-372)     

Content of cholesterol extracted from human skin surface--a possible discriminant of atherosclerosis?]

Basing on the data of Bouissou et al. on an increase of cholesterol content in the skin biopsies in atherosclerosis patients, the cholesterol amount was evaluated after superficial atraumatic rapid treatment of patients palm skin. The optimization of the extraction conditions was performed: the surface skin cholesterol value was constant for individual subjects (variability factor 5%). The range of this value was 1.5-6 Mg/cm2 and it was higher for atherosclerotic patients. No correlations with any conventional plasma lipoprotein parameters were observed. At the same time positive correlation (r = 0.54. p < 0.01) was observed with dyslipoprotein coefficient--(Ch+TG/alpha-Ch). Possible diagnostic significance of this skin cholesterol parameter is discussed.     

Detection and quantitation of low density lipoprotein (LDL) receptors in human liver by ligand blotting, immunoblotting, and radioimmunoassay. LDL receptor protein content is correlated with plasma LDL cholesterol concentration

Low density lipoprotein (LDL) receptor activity has been detected and identified in human liver samples by ligand blotting with biotinylated lipoproteins and by immunoblotting with a monoclonal antibody raised against the bovine adrenal LDL receptor. The molecular weight of the human liver LDL receptor, approximately 132,000 on nonreduced polyacrylamide gels, is identical to that of LDL receptors detected in normal human skin fibroblasts by the same methods. LDL receptor-dependent binding activity in human liver samples has been semi-quantitated by integrating the areas under the peaks after scanning photographs of ligand blots, and receptor protein determined by radioimmunoassay with purified bovine adrenal LDL receptor protein as the standard. There was a highly significant correlation between the values obtained by each method for seven different liver samples (r = 0.948). The LDL receptor protein content of liver membranes from 10 subjects as determined by radioimmunoassay was inversely related to the plasma LDL cholesterol concentration (r = 0.663, p = 0.05) but not to other plasma lipid values, including total plasma cholesterol, high density lipoprotein cholesterol, or plasma triglyceride concentrations.     

Creatine kinase-MB isoenzyme adaptations in stressed human skeletal muscle of marathon runners

The creatine kinase (CK) isoenzyme composition was determined in serial gastrocnemius muscle biopsies obtained from 12 male marathon runners. The mean muscle CK-MB composition significantly increased after chronic exercise (training) from 5.3% (pretraining) to 7.7% (premarathon) as well as after acute exercise (postmarathon) to 10.5% of the total CK activity (P less than 0.05). However, no significant differences in total CK activities were detected. Additionally, mitochondrial CK and CK-BB isoenzymes were present in muscle homogenates. A significant correlation was observed in the increase in mean serum total CK (3,322 U/l) and CK-MB (174 U/l) activities 24 h after the race (r = 0.98, P less than 0.05). These results show that gastrocnemius muscle adapts to long-distance training and racing with increased CK-MB activities and imply that skeletal muscle is the major source of elevated serum CK-MB activities in marathon runners.     

Relationship between adiponectin and metabolic variables in Caribbean offspring of patients with type 2 diabetes mellitus.

AIM: To examine the relationship between adiponectin and metabolic variables in the offspring of patients with type 2 diabetes mellitus. METHODS: Fasting blood samples and anthropometric indices were taken from 34 subjects, offspring of patients with type 2 diabetes, and 24 healthy control subjects without any immediate family history of diabetes. Plasma glucose and serum adiponectin, insulin, triglycerides, total cholesterol, HDL and LDL cholesterol levels were measured, and insulin resistance (IR) was calculated based on the homeostasis model assessment (HOMA) method. RESULTS: Offspring and control subjects were sex-matched, but the offspring were older and had higher body mass index and waist circumference than the control subjects (p < 0.05). The offspring had significantly higher mean fasting plasma glucose concentrations; however, their mean serum insulin, adiponectin, triglyceride, total cholesterol, HDL and LDL cholesterol and HOMA-derived IR levels did not significantly differ from those of the control subjects (p > 0.05). While the negative correlation between serum adiponectin and HDL cholesterol levels in the offspring remained statistically significant after adjusting for the effect of age, sex and BMI (r = -0.37, p < 0.05), the negative correlation between adiponectin and serum triglyceride, LDL cholesterol or IR levels became non-significant after controlling for the above variables (p > 0.05 in all cases). CONCLUSION: The correlation between adiponectin and some known biochemical risk factors for developing diabetes and cardiovascular disease in the offspring of patients with diabetes warrants further study to evaluate its potential in assessing the risk of developing these disorders.     

Correlation between serum cholesterols and trace element uptake in liver,kidney, and blood of hypercholesterolemic mice

The radioactive multitracer technique was applied to the simultaneous determination of the uptake of 17 trace elements (Be, Na, Sc, V, Cr, Mn, Fe, Co, Zn, As, Se, Rb, Sr, Y, Zr, Nb, and Ru) in the liver, kidney, and blood of hypercholesterolemic model mice. The uptakes of Be, Sc, V, Cr, Fe, As, Rb, Y, Zr, Nb, and Ru in liver increased with an increasing feeding period of a cholesterol-rich diet, whereas the uptakes of Zn and Se decreased. Feeding of the diet resulted in a marked increase in serum total cholesterol, triglycerides, and low-density lipoprotein cholesterol. The metabolism of trace elements between cholesterolemic and normal mice was compared with respect to their serum cholesterol levels. A significant positive correlation was found between the concentration of serum triglycerides and liver uptakes of Cr, Fe, and As and a negative correlation for the uptake of Zn. A significant positive correlation was found between the concentrations of serum high- and low-density lipoprotein cholesterols and kidney uptakes of Cr and Rb. A negative correlation was found between the uptake of Be in the blood and the concentration of serum triglycerides. These results suggest that cholesterolemia have some specific effects on the metabolism of some elements.     

Relations between parameters of lipid metabolism and hemostasis in vascular diseases

In 98 patients with arterial insufficiency of arteriosclerotic and diabetic genesis correlation analyses were carried out between total cholesterol, HDL cholesterol, triglycerides, creatinine, blood pressure, platelet counts, platelet function and antithrombin III. Besides the known relations between the parameters of lipid metabolism and blood pressure, correlations were found and analysed between antithrombin III, platelet function, renal function and between platelet counts and HDL cholesterol. The importance of the findings for the diagnosis of vascular insufficiency and the relation to normal values are discussed.     

The correlation of skin blood flow with age, total cholesterol, hematocrit, blood pressure, and hemoglobin

Normal skin blood flow at the deltoid region in 55 men whose ages ranged from 20 to 72 years was measured by the xenon-133 clearance method. In addition, the correlation of skin blood flow with age, systolic blood pressure, total cholesterol, hematocrit, hemoglobin, and total protein was analyzed by multiple regression analysis. The following results were obtained. Normal skin blood flow was found to decrease with increase in age, total cholesterol, and systolic blood pressure and showed a tendency to increase with elevation in hematocrit and hemoglobin values. Of the six parameters examined in the present study, the parameter that showed the strongest correlation with skin blood flow at the deltoid region was age, followed in decreasing order by total cholesterol, hematocrit, systolic blood pressure, and hemoglobin. It could therefore be concluded that age is the most reliable factor in clinically estimating skin blood flow. Furthermore, inasmuch as total cholesterol, hematocrit, systolic blood pressure and hemoglobin values also were correlated with skin blood flow, these values also should be taken in account in the synthetic evaluation of skin blood flow. It was skin blood flow at the deltoid region that was strongly correlated with age. This was followed by systolic blood pressure, hematocrit, and hemoglobin. Total cholesterol showed a weak correlation with age, but total protein did not demonstrate any correlation with skin blood flow and age. The results of the present study show that skin blood flow would be poor in the elderly and in patients with arteriosclerosis, hypertension, and anemia. Since it is suggested that the wound-healing process is delayed in such patients, utmost care should be exercised in treating their wounds.     

Serum and thyroid tissue lipids in patients with thyroid tumors in euthyroidism

Plasma lipids of 24 euthyroid subjects with thyroid adenoma and non-toxic primary differentiated thyroid carcinoma (papillary and follicular types) were assessed and compared with a similar investigation conducted on 20 normal subjects. A parallel study with thyroid tumor tissues examined the lipid changes which occurred in the same group of patients. These were compared with the picture seen in 5 normal thyroids. The investigations examined the changes in total lipids; total, free and esterified cholesterol; total phospholipids; lecithin; cephalin and sphingomyelin; triglycerides and free fatty acids in both serum and thyroid tissue. Compared with normal subjects, the serum lipids were almost identical except for the concentration of free fatty acids which showed significantly lower values in the group with neoplastic changes. Tissue analysis of the cancerous thyroid however revealed a marked rise in virtually all lipid fractions but the cholesterol seemed to dominate the picture. The differential studies of total phospholipids for thyroid tissue membrane lipids further revealed a significant increase in the lecithin and sphingomyelin components of total phospholipids as well as the esterified cholesterol fraction in thyroid carcinoma. The changes in thyrophospholipids were more marked in females normal thyroids than males. An attempt has been made through evaluation of the results derived from differential lipid studies to elucidate the role of some of the various fractions determined and the possible effect of the changes described on thyroid hormone metabolism.     

The total peroxyl radical trapping potential in serum - an assay to define the stage of atherosclerosis

Lipid peroxides were identified among the factors that contribute to the atherosclerotic plaque formation in the arterial wall. We hypothesised that a correlation may exist between the content of antioxidant constituents in the serum and the gravity of atherosclerosis. To this purpose, we have determined the serum total peroxyl radical- trapping potential (TRAP), which is the combined capacity of all antioxidants to neutralize free radicals in serum and followed its variation in hyperlipemic animals in correlation with the stage of atherosclerosis. In addition, we compared TRAP values in the sera of coronary heart disease (CHD) patients, with or without type II diabetes mellitus. Results showed that after 18 weeks of hyperlipemic diet, the mean TRAP values measured in sera isolated from hyperlipemic hamsters exhibited an about 44% decrease, in good agreement with the increase of serum cholesterol and triglycerides. In the 3 groups of CHD patients, TRAP values decreased with about 10% in sera of stable angina patients, 20% in unstable patients, as compared with normal subjects. The lowest TRAP values were detected in the sera of patients with acute myocardial infarction. The results obtained for different experimental animals and for CHD patients sera indicate that the TRAP method, as adapted in our laboratory, is a reliable and reproducible assay, fit to be used in clinical studies as an ex vivo measurable parameter that correlates with the stage of the atherosclerosis.     

Increased glucose disappearance rate after short-term clofibrate administration in normal subjects and in patients with chemical diabetes

Following seven days clofibrate administration, the glucose disappearance rate during an intravenous glucose tolerance test was significantly increased in 6 normal subjects and in 11 patients with chemical diabetes. Both the acute and the total insulin secretory response were unchanged. Though fasting serum levels of free fatty acids, triglycerides, and cholesterol were significantly lowered by treatment, no correlation was found between the decrease in serum lipids and the increase in glucose disappearance rate. It is suggested and clofibrate improves glucose utilization by reducing insulin resistance irrespective of its effects on serum lipids concentration.     

Effect of haptoglobin subtypes on serum lipid levels

Haptoglobin (Hp) subtypes were analysed by two-dimensional high-resolution gel electrophoresis in 81 Norwegian individuals with moderate hypercholesterolemia and in 316 Norwegian control subjects. The frequencies of the genes Hp2SS and Hp2SF were higher in individuals with hypercholesterolemia than in controls but the differences did not reach statistical significance (p = 0.087). Within the control population, no effect of the different Hp subtypes was found on total serum cholesterol, triglycerides or high-density lipoprotein (HDL) cholesterol. However, in the controls a significantly higher frequency of Hp2-2 types was found among those with HDL cholesterol values in the upper quartile as compared to those with HDL cholesterol in the lower quartile. A similar phenomenon was not uncovered in analyses of total serum cholesterol or triglycerides. Our results are in agreement with others which indicate that genes belonging to the Hp polymorphism play a role in predicting an individual's total serum cholesterol level. However, our data indicate that the cholesterol effect is on the HDL rather than on the total cholesterol level.     

Relationship between indices of iron status and coronary risk factors including diabetes and the metabolic syndrome in Saudi subjects without overt coronary disease

There have been inconsistent reports on the relationship between iron status and coronary artery diseases (CAD), and little data on this relationship in non-Caucasian populations.

We assessed dietary iron by questionnaire and measured serum iron and ferritin levels in 270 Saudi male subjects without established CAD, 130 of whom were angiogram negative. Serum lipid profile, glucose, high sensitivity-C reactive protein (hs-CRP), serum soluble intercellular adhesion molecules-1 (sICAM-1), and caeruloplasmin were measured in all subjects.

The angiogram negative patients, had lower serum ferritin (p<0.05) and iron (p<0.0001) levels than the 140 subjects without reported cardiovascular diseases (CVD). Serum iron correlated with serum triglycerides (p<0.0001) and total cholesterol (p<0.05) levels for this latter group and the groups combined. Serum ferritin correlated with serum total cholesterol and low-density lipoprotein (LDL)-cholesterol in the combined group (p<0.05), and was correlated with blood glucose and serum LDL-cholesterol (p<0.05) in the subjects without reported CVD. After adjustment for confounding variables, serum iron levels remained a significant correlate with total calorie intake and serum triglycerides. Serum ferritin also correlated significantly with cholesterol intake and fasting serum total cholesterol. Dietary iron was significantly related to dietary cholesterol and fiber, age, smoking habits, and serum total cholesterol level.

Hence, indices of iron status were related to several coronary risk factors in the Saudi population.     

The rate of phosphocreatine hydrolysis and resynthesis in exercising muscle in humans using 31P-MRS

Time-resolved 31-phosphorus nuclear magnetic resonance spectroscopy (31P-MRS) of the biceps femoris muscles was performed during exercise and recovery in six healthy sedentary male subjects (maximal oxygen uptake; 46.6 +/- 1.7 (SEM) ml.kg-1.min-1), 5 male sprinters (56.2 +/- 2.5), and 5 male long-distance runners (73.6 +/- 2.2). Each performed 4 min of knee flexion exercises at absolute values of 1.63 W and 4.90 W, followed by 5 min of recovery in a prone position in a 2.1 T superconducting magnet with a 67 cm bore. 31P-MRS spectra were recorded every 12.8 s during the rest-exercise-recovery sequence. Computer-aided contour analysis and pixel imaging of phosphocreatine peaks (PCr) and inorganic phosphate (Pi) were performed. The work loads in the present study were selected as mild exercise (1.63 W) and heavy exercise (4.90 W), corresponding to 18-23% and 54-70% of maximal exercise intensity. Long-distance runners showed a significantly smaller decrement in PCr and less acidification at a given exercise intensity compared to those shown by sedentary subjects. The transient responses of PCr and Pi during recovery were characterized by first-order kinetics. After exercise, the recovery rates of PCr and Pi were significantly faster in long-distance runners than in sedentary subjects (P < 0.05). Since it is postulated that PCr resynthesis is controlled by aerobic metabolism and mitochondrial creatine kinase, it is suggested that the faster PCr and Pi recovery rates and decreased acidification seen in long-distance runners during and after exercise might be attributed to their greater capacity for aerobic metabolism.