Excretion of 4-Amino-5-Imidazolecarboxamide and Creatine:creatinine Ratios in Human and Mouse Muscular Dystrophy

Abstract

Excretion of creatine, creatinine, and 4-amino-5-imidazolecarboxamide (AIC) was studied in genetically determined muscular dystrophy in the human and mouse. The AIC excretion was normal in both affected humans and mice as compared with groups of comparably aged controls. The creatine-to-creatinine ratio for human muscular dystrophics was more than four times as great as for their unaffected siblings. Both normal and dystrophic mice showed a "creatinuria" as compared to humans. The creatine-to-creatinine ratio for dystrophic mice was significantly higher than the controls, but the difference was apparent only in the first 2 months of life.

Muscular dystrophy in man: biochemical aspects

“…One of the earliest discovered characteristics, and one which has been extensively confirmed and studied by many workers, is a marked increase in creatine excretion, together with a decrease in urinary creatinine. Thus, to quote from a recent paper by McGeer, McGeer, Miller, Derry & Nichol(1962), affected boys excreted daily on the average 15.2 mg creatine and 10.4 mg creatinine/kg body-weight : the normal values were 8.1 mg and 23.8 mg respectively. (These workers, incidentally, found little or no difference in the rate of excretion of 5-aminoimidazole-4-carboxamide.)…”

“…Thus, to quote from a recent paper by McGeer, McGeer, Miller, Derry & Nichol(1962), affected boys excreted daily on the average 15.2 mg creatine and 10.4 mg creatinine/kg body-weight : the normal values were 8.1 mg and 23.8 mg respectively. (These workers, incidentally, found little or no difference in the rate of excretion of 5-aminoimidazole-4-carboxamide.)…”