Urinary Excretion of Cyclic Adenosine 3′,5′-Monophosphate in Children of Different Ages

Abstract

The urinary excretion of cyclic AMP was investigated in 97 healthy children, 3 months to 16 years old. When the excretion was expressed as μmol/24 h an increase with age (r = 0.693, P < 0.001) and an increase with body weight (r = 0.700, P < 0.001) were found to be quite similar. In relation to surface area, the average excretion for children up to 9½ years old was 4.45 ± 1.71 μmol/m² in contrast with 2.22 ± 0.66 μmol/m² in older children (P < 0.001). The decline appears to be associated with approaching puberty. When cAMP excretion was related to urinary creatinine, an inverse correlation with age was found (r = −0.772, P < 0.001). In the youngest category, 3 months to 4 years old, the ratio was 9.26 ± 1.49 μmol/g creatinine vs 4.67 ± 1.05 μmol/g creatinine in the age group 12 to 16 years old (P < 0.001), which compares closely with the normal adult average of 4.34 ± 1.25 μmol/g creatinine found in our previous study. Throughout there was no evidence of sex differentiation.