Metabolic intermediates, enzymes and lysosomal activity in aortas of spontaneously hypertensive rats.
Metabolic intermediate levels, glycolytic and Krebs cycle enzyme activities and lysosomal acid hydrolase activities were measured in aortas of spontaneously hypertensive (SHR) versus normotensive (WKY) rats. In the hypertensive aortas the level of lactate, the ratio of lactate to glucose and of lactate to malate was higher in the SHR than WKY aortas. In the hypertensive aortas the obvious shift of metabolism toward higher rate of glycolysis was associated with decreased activity of malate dehydrogenase and espically of lipoamide dehydrogenase. The latter is an essential compoenent of the alpha-ketoglutarate and pyruvate dehydrogenase enzyme complexes and it appears that these complexes are among the sites of arterialmetavolism which are primarily altered by the elevated blood pressure, resulting in increased production of lactate. The activity of the marker lysosomal enzyme N-acetyl-beta-glucosaminidase was unequivocally elevated in the hypertensive aortas. The activity of beta-glucuronidase exhibited incogruous differences between the SHR and WKY aortas and the activity of aortic acid phosphatase did not differ in the two rat strains. The results are discussed in relation to arterial injury, permeability, and atherogenesis.