Activity of two components of serum ribonuclease under conditions of physical exercise

The chronically reserpinized rat: decreased glycolytic activity in the submandibular gland

Some of the enzymes and metabolites of the glycolytic pathway of an animal model for cystic fibrosis (the chronically reserpine-treated rat) were investigated. The activities of the enzymes phosphofructokinase (P less than 0.002), enolase (P less than 0.03), pyruvate kinase (P less than 0.005), and lactate dehydrogenase (P less than 0.009) were decreased whereas the activity of glycerol-3-phosphate dehydrogenase was unaffected in the submandibular glands of the treated animals. For metabolites, the reserpine treatment resulted in an increased concentration of glycogen (P less than 0.0002) and phosphoenolpyruvate (P less than 0.001) and a decreased concentration of pyruvate (P less than 0.005) and lactate (P less than 0.002) in the glands. The concentration of glucose and glycerate-2-phosphate was unaffected. The perchloric acid-soluble part of the proteins was also increased (P less than 0.0001) in the submandibular glands of the reserpine-treated animals, as was the activity of ribonuclease. These findings point to a disturbance in the metabolism of glucose and a possible acidosis in the submandibular glands of this animal model for cystic fibrosis.

Cystic fibrosis-like changes in saliva of healthy persons subjected to anaerobic exercise

The biochemical composition of saliva secreted by healthy persons and by heterozygotes and homozygotes of cystic fibrosis at rest and by healthy persons subjected to aerobic or anaerobic effort were compared. In the saliva from cystic fibrosis homozygotes at rest substantial increases of the activity of ribonuclease (p less than 0.001) and of the concentrations of protein (p less than 0.001), lactate (p less than 0.001), sodium (p less than 0.001), potassium (p less than 0.01) and calcium (p less than 0.05) were found in comparison with saliva from healthy persons at rest. In the saliva from cystic fibrosis heterozygotes at rest similar but less pronounced changes were seen. After anaerobic exercise these biochemical parameters were increased in the saliva of healthy persons and mimicked the values of cystic fibrosis saliva. However, after aerobic effort no changes other than a slightly increased ribonuclease activity were seen in the saliva of healthy persons. This indicates that salivary glands of cystic fibrosis patients, at rest, are in the same state of lactate acidosis and energy depletion as these glands are in healthy persons after anaerobic work.

Effect of exercise on ribonuclease activity in rat skeletal muscle

Distribution of ribonuclease activity (measured at pH 7.6) in subcellular fractions of homogenates of rat skeletal muscle was investigated in sedentary animals and after 8 weeks running program. Training increased ribonuclease activity (expressed as units of enzyme per g of muscle protein). There was no increase in nuclear fraction, but in both cytoplasmic and mitochondrial fractions the RNA-ase activity increased 42% and 45% respectively.