Immunoassay of the cardiac-specific isoform of troponin-I in the diagnosis of heart muscle damage

Abstract

Hypoxanthine is a central metabolite in ATP metabolism and its salvage to IMP is catalysed by hypoxanthine phosphoribosyltransferase (HPRT: EC 2.4.2.8.).Since deficiency of this enzyme in man causes profound neurological dysfunction and testicular atrophy, a regular supply of substrate should be available. However, only ATP depletion has been proven to produce a marked increase in hypoxanthine output (Harkness et al., 1983), but ATP depletion rarely occurs in human tissues under normal conditions. This study was set up to investigate hypoxanthine output under conditions of ATP turnover rather than depletion. This was achieved by exercising at low-tomoderate levels of ATP use and examining hypoxanthine, xanthine and urate output.Exercise was performed for 2 min on a bicycle ergometer by ten normal volunteers (five men and five women) at five different work rates on five consecutive days of one week.