Urinary excretion of cyclic nucleotides and principal electrolytes in healthy humans of different ages.

Urinary excretion of cyclic AMP, cyclic GMP, inorganic phosphorus, calcium, sodium, potassium and creatinine was measured in 138 healthy male and 104 healthy female humans from 2 to 68 years old. The range of cyclic nucleotide excretion was as follows: cyclic AMP (mumol/day), 1.01-10.89; cyclic GMP (mumol/day), 0.13-2.00; cyclic AMP (mumol/g creatinine), 1.52-8.93; cyclic GMP (mumol/g creatinine), 0.11-1.87. The 242 volunteers were grouped into seven classes according to age: A, 2-9 years old; B, 10-19; C, 20-29; D, 30-39; E, 40-49; F, 50-59 and G, 60-68. Average excretion (mumol/day) of cyclic AMP in class A (2.62 +/- 0.29 for males and 2.30 +/- 0.18 for females) was significantly smaller than that in other classes (4.59 +/- 0.12 for males and 3.90 +/- 0.13 for females) (p less than 0.01). Such a significant difference was not observed in cyclic GMP excretion. In terms of mumol/g creatinine, however, average excretion of both cyclic AMP and cyclic GMP in class A was greater than that in other classes. The amounts of urinary cyclic AMP and cyclic GMP (mumol/day) were correlated with age in the subjects from 2 to 16 years. A reverse correlation between the amounts of both nucleotides (mumol/g creatinine) and age was found in the young subjects. No correlation between the excretion of either urinary cyclic nucleotide and age was found in adults. A significantly positive correlation between cyclic AMP (mumol/day) and inorganic phosphorus (g/day) was found (r = 0.50 for males and 0.56 for females) (p less than 0.01). This correlation suggests that urinary cyclic AMP might reflect the activity of parathyroid hormone in normal humans. There was no significant correlation between cyclic GMP and electrolytes tested. The above results are considered to provide basic data for clinical evaluation of relevant disorders.