Osthol Ameliorates Kidney Damage and Metabolic Syndrome Induced by a High-Fat/High-Sugar Diet.

Excessive intake of fructose results in metabolic syndrome (MS) and kidney damage, partly mediated by its metabolism by fructokinase-C or ketohexokinase-C (KHK-C). Osthol has antioxidant properties, is capable of regulating adipogenesis, and inhibits KHK-C activity. Here, we examined the potential protective role of osthol in the development of kidney disease induced by a Western (high-fat/high-sugar) diet. Control rats fed with a high-fat/high-sugar diet were compared with two groups that also received two different doses of osthol (30 mg/kg/d or 40 mg/kg/d body weight BW). A fourth group served as a normal control and received regular chow. At the end of the follow-up, kidney function, metabolic markers, oxidative stress, and lipogenic enzymes were evaluated. The Western diet induced MS (hypertension, hyperglycemia, hypertriglyceridemia, obesity, hyperuricemia), a fall in the glomerular filtration rate, renal tubular damage, and increased oxidative stress in the kidney cortex, with increased expression of lipogenic enzymes and increased kidney KHK expression. Osthol treatment prevented the development of MS and ameliorated kidney damage by inhibiting KHK activity, preventing oxidative stress via nuclear factor erythroid 2-related factor (Nrf2) activation, and reducing renal lipotoxicity. These data suggest that the nutraceutical osthol might be an ancillary therapy to slow the progression of MS and kidney damage induced by a Western diet.

A predominant isoform of fructokinase, HbFRK2, is involved in Hevea brasiliensis (para rubber tree) latex yield and regeneration.

Fructokinase (FRK) mediates fructose phosphorylation to regulate the carbon flow and its assignment to sink tissues. Out of five HbFRKs in the genome of the rubber tree, three (HbFRK1-3) that were highly expressed in latex (cytoplasm of laticifers) were isolated and examined. According to phylogenetic analysis and intracellular location experiment, both HbFRK2 and HbFRK3 were highly possible to be expressed in cytosol, while HbFRK1 was in plastid. As the predominant isoform in laticifers, HbFRK2 had the highest transcripts, followed by HbFRK3 and HbFRK1. In enzymatic function, HbFRK2 also showed the highest affinity for fructose. To examine the roles of FRKs in latex yield and regeneration, changes in HbFRKs were examined when latex outflow from the trees were increased through two experimental interventions. In the first approach, tapping was initiated on previously untapped trees, resulting in latex yield increasing with consecutive tapping at the initial stage before it stabilized. In the second approach, latex yield from trees that were already in regular tapping was stimulated by treatment with the ethylene-based yield stimulant, ethephon. Using either method to induce an increase in latex yield, the abundance of HbFRK2 and HbFRK3 in transcripts, was increased. This development, which was especially marked in HbFRK2, may reflect a strengthening of glycolysis to meet the carbon flux and energy demands for increased rubber biosynthesis to replace rubber lost in the increased latex yield. Our results, therefore, suggest that HbFRK2 plays a critical role in fructose catabolism to facilitate rubber regeneration in the commercially exploited rubber tree.

Fluid Intake Restriction Concomitant to Sweetened Beverages Hydration Induce Kidney Damage.

Currently, there is the paradox of low water intake but increased intake of sugar-sweetened beverages (SB) in several populations; those habits are associated with an increased prevalence of metabolic derangements and greater chronic disease mortality. Persistent heat dehydration and increased SB intake stimulate the continued release of vasopressin and overactivation of the polyol-fructokinase pathway, synergizing each other, an effect partially mediated by oxidative stress. The objective of the present study was to evaluate whether water restriction concurrent with SB hydration can cause renal damage by stimulating similar pathways as heat dehydration. Three groups of male Wistar rats (n = 6) were fluid restricted; from 10 am to 12 pm animals could rehydrate with tap water (W), or sweetened beverages, one prepared with 11% of a fructose-glucose combination (SB), or with the noncaloric edulcorant stevia (ST). A normal control group of healthy rats was also studied. The animals were followed for 4 weeks. Markers of dehydration and renal damage were evaluated at the end of the study. Fluid restriction and water hydration mildly increased urine osmolality and induced a 15% fall in CrCl while increased the markers of tubular damage by NAG and KIM-1. Such changes were in association with a mild overexpression of V1a and V2 renal receptors, polyol fructokinase pathway overactivation, and increased renal oxidative stress with reduced expression of antioxidant enzymes. Hydration with SB significantly amplified those alterations, while in stevia hydrated rats, the changes were similar to the ones observed in water hydrated rats. These data suggest that current habits of hydration could be a risk factor in developing kidney damage.

Restricted Water Intake and Hydration with Fructose-Containing Beverages during Infancy Predispose to Aggravate an Acute Renal Ischemic Insult in Adolescent Rats.

We aimed to investigate the effects of chronic fluid restriction and hydration with a sweetened beverage (SB) in rats from weaning until adolescence, in a posterior acute kidney injury (AKI) event induced by ischemia-reperfusion (I/R). We followed 5 groups of weaning rats: control group (C); two groups with 22 h/day fluid restriction, a group hydrated for two hours with water (-W) and a group hydrated with SB; one group receiving SB ad libitum all day (+SB); and one group in which water consumption was increased using a gel diet. The rats that reached adolescence were submitted to I/R. Fluid restriction and/or SB hydration induced mild renal alterations that were significantly accentuated in the -SB group and resulted in worse outcomes after I/R-induced AKI that resulted in a catastrophic fall in creatinine clearance and diffuse acute tubular necrosis. In summary, low tap water intakes, as well as SB intake in infancy, prompt kidney worse outcomes in a later event of AKI during adolescence and both insults magnify kidney damage. Studies on hydration habits in children are recommended to disclose the potentially harmful effects that those behavioral patterns might carry to future renal health.

Antioxidant supplements as a novel mean for blocking recurrent heat stress-induced kidney damage following rehydration with fructose-containing beverages.

Recently repeated heat stress and dehydration have been reported to cause oxidative stress and kidney damage that is enhanced by rehydrating with fructose solutions. We hypothesized that antioxidants might provide a novel way to prevent kidney damage. To test this hypothesis, mild heat stress was induced by exposing rats to 37 °C during 1 h in a closed chamber. The supplementation with water-soluble antioxidants (Antiox), ascorbic acid 1% plus N-acetyl cysteine 600 mg/L was done either in the 10% fructose 2 h rehydration fluid immediately after heat stress (Fructose 10% + Antiox), and/or in the tap water (Water + Antiox) for the remainder of the day, or in both fluids. After 4 weeks, control rats exposed to heat with fructose rehydration developed impaired renal function, tubular injury, intrarenal oxidative stress, a reduction in Nrf2-Keap1 antioxidant pathway, stimulation of vasopressin and the intrarenal polyol-fructokinase pathway. In contrast, dosing the antioxidants in the tap water (i.e., before the heat exposure and rehydration with fructose) preserved renal function, prevented renal tubule dysfunction and avoided the increase in systemic blood pressure. These effects were likely due to the amplification of the antioxidant defenses through increased Nrf2 nuclear translocation stimulated by the antioxidants and by the prevention of polyol fructokinase pathway overactivation. More studies to understand the mechanisms implicated in this pathology are warranted as there is recent evidence that they may be operating in humans as well.

Searching whole genome sequences for biochemical identification features of emerging and reemerging pathogenic Corynebacterium species.

Biochemical tests are traditionally used for bacterial identification at the species level in clinical microbiology laboratories. While biochemical profiles are generally efficient for the identification of the most important corynebacterial pathogen Corynebacterium diphtheriae, their ability to differentiate between biovars of this bacterium is still controversial. Besides, the unambiguous identification of emerging human pathogenic species of the genus Corynebacterium may be hampered by highly variable biochemical profiles commonly reported for these species, including Corynebacterium striatum, Corynebacterium amycolatum, Corynebacterium minutissimum, and Corynebacterium xerosis. In order to identify the genomic basis contributing for the biochemical variabilities observed in phenotypic identification methods of these bacteria, we combined a comprehensive literature review with a bioinformatics approach based on reconstruction of six specific biochemical reactions/pathways in 33 recently released whole genome sequences. We used data retrieved from curated databases (MetaCyc, PathoSystems Resource Integration Center (PATRIC), The SEED, TransportDB, UniProtKB) associated with homology searches by BLAST and profile Hidden Markov Models (HMMs) to detect enzymes participating in the various pathways and performed ab initio protein structure modeling and molecular docking to confirm specific results. We found a differential distribution among the various strains of genes that code for some important enzymes, such as beta-phosphoglucomutase and fructokinase, and also for individual components of carbohydrate transport systems, including the fructose-specific phosphoenolpyruvate-dependent sugar phosphotransferase (PTS) and the ribose-specific ATP-binging cassette (ABC) transporter. Horizontal gene transfer plays a role in the biochemical variability of the isolates, as some genes needed for sucrose fermentation were seen to be present in genomic islands. Noteworthy, using profile HMMs, we identified an enzyme with putative alpha-1,6-glycosidase activity only in some specific strains of C. diphtheriae and this may aid to understanding of the differential abilities to utilize glycogen and starch between the biovars.

Mesoamerican Nephropathy or Global Warming Nephropathy?

BACKGROUND: An epidemic of chronic kidney disease (CKD) of unknown cause has emerged along the Pacific Coast of Central America. The disease primarily affects men working manually outdoors, and the major group affected is sugarcane workers. The disease presents with an asymptomatic rise in serum creatinine that progresses to end-stage renal disease over several years. Renal biopsies show chronic tubulointerstitial disease. While the cause remains unknown, recent studies suggest that it is driven by recurrent dehydration in the hot climate. Potential mechanisms include the development of hyperosmolarity with the activation of the aldose reductase-fructokinase pathway in the proximal tubule leading to local injury and inflammation, and the possibility that renal injury may be the consequence of repeated uricosuria and urate crystal formation as a consequence of both increased generation and urinary concentration, similar to a chronic tumor lysis syndrome. The epidemic is postulated to be increasing due to the effects of global warming. SUMMARY: An epidemic of CKD has led to the death of more than 20,000 lives in Central America. The cause is unknown, but appears to be due to recurrent dehydration. Potential mechanisms for injury are renal damage as a consequence of recurrent hyperosmolarity and/or injury to the tubules from repeated episodes of uricosuria. KEY MESSAGES: The epidemic of CKD in Mesoamerica may be due to chronic recurrent dehydration as a consequence of global warming and working conditions. This entity may be one of the first major diseases attributed to climate change and the greenhouse effect.

Mechanisms by Which Dehydration May Lead to Chronic Kidney Disease.

Dehydration, a condition that characterizes excessive loss of body water, is well known to be associated with acute renal dysfunction; however, it has largely been considered reversible and to be associated with no long-term effects on the kidney. Recently, an epidemic of chronic kidney disease has emerged in Central America in which the major risk factor seems to be recurrent heat-associated dehydration. This has led to studies investigating whether recurrent dehydration may lead to permanent kidney damage. Three major potential mechanisms have been identified, including the effects of vasopressin on the kidney, the activation of the aldose reductase-fructokinase pathway, and the effects of chronic hyperuricemia. The discovery of these pathways has also led to the recognition that mild dehydration may be a risk factor in progression of all types of chronic kidney diseases. Furthermore, there is some evidence that increasing hydration, particularly with water, may actually prevent CKD. Thus, a whole new area of investigation is developing that focuses on the role of water and osmolarity and their influence on kidney function and health.

Functional characterization of Synechococcus amylosucrase and fructokinase encoding genes discovers two novel actors on the stage of cyanobacterial sucrose metabolism.

Plants and most cyanobacteria metabolize sucrose (Suc) with a similar set of enzymes. In Synechococcus sp. PCC 7002, a marine cyanobacterium strain, genes involved in Suc synthesis (spsA and sppA) have been characterized; however, its breakdown was still unknown. Indeed, neither invertase nor sucrose synthase genes, usually found in plants and cyanobacteria, were found in that Synechococcus genome. In the present study, we functionally characterized the amsA gene that codes for an amylosucrase (AMS), a glycoside-hydrolase family 13 enzyme described in bacteria, which may catabolyze Suc in Synechococcus. Additionally, we identified and characterized the frkA gene that codes for a fructokinase (FRK), enzyme that yields fructose-6P, one of the substrates for Suc synthesis. Interestingly, we demonstrate that spsA, sppA, frkA and amsA are grouped in a transcriptional unit that were named Suc cluster, whose expression is increased in response to a salt treatment. This is the first report on the characterization of an AMS and FRK in an oxygenic photosynthetic microorganism, which could be associated with Suc metabolism.

Hyperosmolarity drives hypertension and CKD--water and salt revisited.

An epidemic of chronic kidney disease (CKD) in Mesoamerica is providing new insights into the mechanisms by which salt and water might drive hypertension and CKD. Increasingly, evidence suggests that recurrent dehydration and salt loss might be a mechanism that causes CKD, and experimental studies suggest a key role for increased plasma osmolarity in activating both intrarenal (polyol-fructokinase) and extrarenal (vasopressin) pathways that drive renal injury. Thus, we propose that water and salt might influence blood pressure and kidney disease through the timing and combination of their intake, which affect plasma osmolarity as well as intrarenal and extrarenal mechanisms of renal injury. The type of fluid intake might also be important, as fluids containing fructose can trigger activation of these pathways. Future studies should investigate the effects of salt, sugar and fluid intake on plasma osmolarity as a potential pathogenetic mechanism in renal injury and high blood pressure.

High-fat and high-sucrose (western) diet induces steatohepatitis that is dependent on fructokinase.

UNLABELLED: Fructose intake from added sugars has been implicated as a cause of nonalcoholic fatty liver disease. Here we tested the hypothesis that fructose may interact with a high-fat diet to induce fatty liver, and to determine if this was dependent on a key enzyme in fructose metabolism, fructokinase. Wild-type or fructokinase knockout mice were fed a low-fat (11%), high-fat (36%), or high-fat (36%) and high-sucrose (30%) diet for 15 weeks. Both wild-type and fructokinase knockout mice developed obesity with mild hepatic steatosis and no evidence of hepatic inflammation on a high-fat diet compared to a low-fat diet. In contrast, wild-type mice fed a high-fat and high-sucrose diet developed more severe hepatic steatosis with low-grade inflammation and fibrosis, as noted by increased CD68, tumor necrosis factor alpha, monocyte chemoattractant protein-1, alpha-smooth muscle actin, and collagen I and TIMP1 expression. These changes were prevented in the fructokinase knockout mice. CONCLUSION: An additive effect of high-fat and high-sucrose diet on the development of hepatic steatosis exists. Further, the combination of sucrose with high-fat diet may induce steatohepatitis. The protection in fructokinase knockout mice suggests a key role for fructose (from sucrose) in this development of steatohepatitis. These studies emphasize the important role of fructose in the development of fatty liver and nonalcoholic steatohepatitis.

Synergistic effect of uricase blockade plus physiological amounts of fructose-glucose on glomerular hypertension and oxidative stress in rats.

Fructose in sweetened beverages (SB) increases the risk for metabolic and cardiorenal disorders, and these effects are in part mediated by a secondary increment in uric acid (UA). Rodents have an active uricase, thus requiring large doses of fructose to increase plasma UA and to induce metabolic syndrome and renal hemodynamic changes. We therefore hypothesized that the effects of fructose in rats might be enhanced in the setting of uricase inhibition. Four groups of male Sprague-Dawley rats (n = 7/group) were studied during 8 wk: water + vehicle (V), water + oxonic acid (OA; 750 mg/k BW), sweetened beverage (SB; 11% fructose-glucose combination) + V, and SB + OA. Systemic blood pressure, plasma UA, triglycerides (TG), glucose and insulin, glomerular hemodynamics, renal structural damage, renal cortex and liver UA, TG, markers of oxidative stress, mitDNA, fructokinase, and fatty liver synthase protein expressions were evaluated at the end of the experiment. Chronic hyperuricemia and SB induced features of the metabolic syndrome, including hypertension, hyperuricemia, hyperglycemia, and systemic and hepatic TG accumulation. OA alone also induced glomerular hypertension, and SB alone induced insulin resistance. SB + OA induced a combined phenotype including metabolic and renal alterations induced by SB or OA alone and in addition also acted synergistically on systemic and glomerular pressure, plasma glucose, hepatic TG, and oxidative stress. These findings explain why high concentrations of fructose are required to induce greater metabolic changes and renal disease in rats whereas humans, who lack uricase, appear to be much more sensitive to the effects of fructose.

Fructose acutely stimulates NHE3 activity in kidney proximal tubule.

BACKGROUND/AIMS: Fructose causes a sodium-sensitive hypertension and acutely reduces the urinary Na+ excretion, suggesting that it may regulate the activity of renal tubular sodium transporters. NHE3 is highly expressed in proximal tubule (PT), along with proteins that mediate fructose transport and metabolism. The present work was outlined to investigate whether fructose modulates proximal NHE3 activity and to elucidate the molecular mechanisms underlying this modulation. METHODS/RESULTS: Using in vivo stationary microperfusion, we observed that fructose stimulates NHE3 mediated JHCO3- reabsorption. The MAPK pathway is not involved in this activation, as demonstrated by using of MEK/MAPK inhibitors, whereas experiments using a PKA inhibitor suggest that PKA inhibition plays a role in this response. These results were confirmed in vitro by measuring the cell pH recovery rate after NH4Cl pulse in LLC-PK1, a pig PT cell line, which showed reduced cAMP levels and NHE3 phosphorylation at serine-552 (PKA consensus site) after fructose treatment. CONCLUSIONS: NHE3 activity is stimulated by fructose, which increases proximal tubule Na+ reabsorption. The molecular mechanisms involved in this process are mediated, at least in part, by downregulation of the PKA signaling pathway. Future studies are needed to address whether fructose-stimulated NHE3 activity may contribute to renal injury and hypertension.

Minor participation of cAMP on the protein kinase phosphorylation of mitochondrial and cytosolic fractions from Ascaris suum: a comparative study with porcine heart muscle.

In contrast to porcine heart muscle in which cAMP effectively activated the phosphorylation of cytosolic proteins, cAMP exerted a minor effect on the phosphorylation of proteins from the soluble fraction of Ascaris suum muscle. Similarly, cAMP did not enhance the kinase activity in the mitochondrial membranes from porcine heart and A. suum, although major differences in protein phosphorylation were observed between both fractions. However, cAMP-dependent protein kinases (PKA) were evidenced in the parasitic soluble mitochondrial fraction, since the phosphorylation of histone IIA and kemptide was augmented in this fraction, in the presence of cAMP. An increase in the phosphorylation of exogenously added A. suum phosphofructokinase was also obtained when cAMP was added to the parasite soluble mitochondrial fraction. The phosphorylation of phosphofructokinase by this fraction was inhibited when kemptide and cAMP were included in the reaction mixture, suggesting substrate competition for the same PKA. Although PKI (6-22), a reported inhibitor of the catalytic subunit of mammalian cAMP-dependent PKAs, did not affect the endogenous phosphorylation of proteins in the various A. suum fractions, an inhibition on the phosphorylation of exogenously added kemptide and phosphofructokinase was observed when PKI (6-22) was incubated with the parasite mitochondrial soluble fraction.

Subcellular distribution and kinetic properties of cytosolic and non-cytosolic hexokinases in maize seedling roots: implications for hexose phosphorylation.

Hexose phosphorylation by hexokinases plays an important role in glycolysis, biosynthesis and control of sugar-modulated genes. Several cytosolic hexokinase and fructokinase isoforms have been characterized and organelle-bound hexokinases have also been detected in higher plants. In this study a hexokinase activity is described that is inhibited by ADP (K(i)=30 microM) and mannoheptulose (K(i) congruent with 300 microM) in non-cytosolic fractions (mitochondria, Golgi apparatus and microsomes) obtained from preparations of seedling roots of maize (Zea mays L.). The catalytic efficiency (Vmax/Km) for both ATP and glucose in all non-cytosolic hexokinase fractions is more than one order of magnitude higher than that of cytosolic hexokinase and fructokinases. Low (30%) or no ADP and mannoheptulose inhibition is observed with hexokinase and fructokinase activities derived from the cytosolic compartment obtained after ion exchange and affinity chromatography. The soluble fructokinase (FK) shows fructose cooperativity (Hill n>2). The Vmax/Km ratio is about 3-fold higher for ATP than for other NTPs and no difference for hexose phosphorylation efficiencies is found between cytosolic hexokinase and fructokinase isoforms (FK1, FK2) with ATP as substrate. The K(i) for fructose inhibition is 2 mM for FK1 and 25 mM for FK2. The data indicate that low energy-charge and glucose analogues preferentially inhibit the membrane-bound hexokinases possibly involved in sugar-sensing, but not the cytosolic hexokinases and fructokinases.

The effect of diazepan and exercise training on selected biochemical and histochemical properties of rat skeletal muscle.

The effects of chronic diazepam (D) treatment and exercise training on total body mass (TBM), microsomal protein yield (MPY), calcium uptake by fragmented sarcoplasmic reticulum (SR), muscle fibre cross-sectional area, and both PFK and SDH activities were investigated in the tibialis anterior (TA), soleus (Sol), and plantaris (Plt) muscles of 50 male albino Sprague-Dawley rats. Rats were assigned randomly to control (C), sprint-trained (S), or endurance-trained (E) groups. Training was of 12 weeks duration. One-half of each group received daily intraperitoneally D doses of 5 mg kg-1 of TBM. Exercise reduced TBM (p < 0.05); increased the relative BM of the TA (E = 2.02 +/- 0.02, p < 0.01) and Plt (E = 1.15 +/- 0.02, p < 0.01; S = 1.13 +/- 0.03, p < 0.01), as well as the Ca++ uptake of the Sol SR (C = 0.08 +/- 0.02, E = 0.16 +/- 01, p < 0.05). MPY was elevated in S-Sol (C = 1.12 +/- 0.6, S = 1.52 +/- 0.1, p < 0.01). D elevated Sol MPY as well as TA PFK. S-trained animals had lower mean fibre areas than the E-trained (D-treated and untreated) animals. The elevated relative masses of TA and Plt are explained by a decreased TBM with exercise. The increased Ca++ uptake of the Sol indicates that E enhances this function, and the increased MPY probably implies an increased SR. The D could be responsible for the D-elevated Sol MPY as well as the TA PFK. El D did not reduce neuromuscular activity to a level adversely affecting oxidative enzyme activity, but in the case of PFK activity in the TA muscle, such a reduction was evident.

The effect of diazepan and exercise training on selected biochemical and histochemical properties of rat skeletal muscle

The effects of chronic diazepan (D) treatment and exercise training on total body mass (TBM), microsomal protein yield (MPY), calcium uptake by fragmented sarcoplasmic reticulum (SR), muscle fibre cross-sectional area, and both PFK and SDH activities were investigated in the tibialis anterior (TA), soleus (Sol), and plantaris (Plt) muscles of 50 male albino Sprague-Dawley rats. Rats were assigned randomly to control (C), sprint-trained (S), or endurance-trained (E) groups. Training was of 12 weeks duration. One-half of each group received daily intraperitoneally D doses of 5 mg kg(-1) of TBM. Exercise reduced TBM (p<0.05); increased the relative BM of the TA (E=2.02+0.02, p<0.01) and Plt (E=1.15+0.02, p<0.01; S=1.13+0.03, p<0.01), as well as the Ca++ uptake of the Sol SR (C=0.08+0.02, E=0.16+01, p<0.05). MPY was elevated in S-Sol (C=1.12+0.6, S=1.52+0.1, p<0.01). Delevated Sol MPY as well as TA PFK. S-trained animals had lower mean fibre areas than the E-trained (D-treated and untreated) animals. The elevated relative masses of TA and Plt are explained by a decreased TBM with exercise. The increased Ca++ uptake of the Sol indicates that E enhances this function, and the increased MPY probably implies an increased SR. The D could be responsible for the D-elevated Sol MPY as well as the TA PFK. El D did not reduce neuromuscular activity to a level adversely affecting oxidative enzyme activity, but in the case of PFK activity in the TA muscle, such a reduction was evident. (AU)

The effect of diazepan and exercise training on selected biochemical and histochemical properties of rat skeletal muscle

The effects of chronic diazepan (D) treatment and exercise training on total body mass (TBM), microsomal protein yield (MPY), calcium uptake by fragmented sarcoplasmic reticulum (SR), muscle fibre cross-sectional area, and both PFK and SDH activities were investigated in the tibialis anterior (TA), soleus (Sol), and plantaris (Plt) muscles of 50 male albino Sprague-Dawley rats. Rats were assigned randomly to control (C), sprint-trained (S), or endurance-trained (E) groups. Training was of 12 weeks duration. One-half of each group received daily intraperitoneally D doses of 5 mg kg(-1) of TBM. Exercise reduced TBM (p<0.05); increased the relative BM of the TA (E=2.02+0.02, p<0.01) and Plt (E=1.15+0.02, p<0.01; S=1.13+0.03, p<0.01), as well as the Ca++ uptake of the Sol SR (C=0.08+0.02, E=0.16+01, p<0.05). MPY was elevated in S-Sol (C=1.12+0.6, S=1.52+0.1, p<0.01). Delevated Sol MPY as well as TA PFK. S-trained animals had lower mean fibre areas than the E-trained (D-treated and untreated) animals. The elevated relative masses of TA and Plt are explained by a decreased TBM with exercise. The increased Ca++ uptake of the Sol indicates that E enhances this function, and the increased MPY probably implies an increased SR. The D could be responsible for the D-elevated Sol MPY as well as the TA PFK. El D did not reduce neuromuscular activity to a level adversely affecting oxidative enzyme activity, but in the case of PFK activity in the TA muscle, such a reduction was evident.