title: Lysosomal enzymes in the heart of the genetically diabetic mouse.
abstract: The purpose of the present study was to determine the role of cardiac lysosomal enzymes in the pathogenesis of the cardiomyopathy that develops in the genetically diabetic C57BL/KsJ db+/db+ mice. Db+/db+ mice and littermate controls were sacrificed as age-matched pairs between 5 and 26 weeks of age. C57BL/6J ob/ob mice and littermates served as other controls. Following anesthesia, the hearts were excised, homogenized, and the following enzymatic activities measured: N-acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, beta-glucosaminidase, aryl sulfatase, alpha-mannosidase, alpha-glucosidase, beta-galactosidase, beta-glucosidase, total rho-nitrophenyl phosphatase, acid phosphatase. and 5'-phosphodiesterase type IV. There is a progressive decrease in cardiac lysosomal enzyme activities of db+/db+ mice for the period 5 to 21 weeks of age. All enzyme activity is depressed significantly during the 9- to 21-week interval: alpha-glucosidase, beta-glucosidase, alpha-mannosidase, beta-galactosidase, acid phosphatase, N-acetyl-beta-galactosaminidase, 5'-phosphodiesterase type IV, and total rho-nitrophenyl phosphatase are reduced approximately 10 to 20 per cent, whereas beta-glucosaminidase, aryl sulfatase, and N-acetyl-beta-glucosaminidase are decreased almost 40 to 50 per cent. In contrast, cardiac lysosomal enzymic activity in the ob/ob mice does not differ significantly from controls aside from aryl sulfatase (20 per cent decrease) and beta-glucosidase (10 per cent decrease). This decrease in lysosomal enzyme activity can explain the accumulation of large residual bodies and interstitial material that occurs in the myocardium of the db+/db+ animals as part of the cardiomyopathy.
mesh_terms: D000118:Acetylglucosaminidase / Q000378:metabolism; D000818:Animals; D001192:Arylsulfatases / Q000378:metabolism; D001786:Blood Glucose; D001835:Body Weight; D009202:Cardiomyopathies / Q000201:enzymology* / Q000209:etiology; D003920:Diabetes Mellitus / Q000201:enzymology / Q000235:genetics*; D005260:Female; D005966:Glucuronidase / Q000378:metabolism; D006321:Heart / Q000033:anatomy & histology; D008247:Lysosomes / Q000201:enzymology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009929:Organ Size
chemical_list: D001786:Blood Glucose; D001192:Arylsulfatases; D005966:Glucuronidase; D000118:Acetylglucosaminidase