Urinary excretion of adenosine 3',5'-monophosphate and guanosine 3',5'-monophosphate in normal children and those with cystic fibrosis.

The urinary excretion of adenosine 3',5'-monophosphate (cyclic AMP) and guanosine 3',5'-monophosphate (cyclic 
GMP) was examined in 98 normal children and 46 children with 
cystic fibrosis between the ages of 9 months and 18 yr. 
Diurnal variations in cyclic AMP and cyclic GMP excretion were observed 
in subjects from either group, and peak levels of cyclic nucleotide 
excretion were generally observed during the period of 0700 to 2100 
h. Excretion rates (mumol/day) of cyclic AMP and cyclic GMP increased 
significantly with age. When cyclic AMP and cyclic GMP excretion rates 
were normalized for urinary creatine, or body weight, the values declined 
significantly with age in both groups of patients. Cyclic GMP excretion 
normalized for body surface area also decreased with age, while the 
value for cyclic AMP (2.86 plus or minus 0.08 mumol/day/m2, mean 
plus or minus SE) was constant with age in both normals 
and cystic fibrosis children. With some comparisons of age groups there 
were significant differences in cyclic nucleotide excretion between normal subjects and 
children with cystic fibrosis. The differences noted were dependent upon the 
methods used to normalize excretion rates (urinary creatine, body weight, surface 
area, and the ratio of cyclic AMP to cyclic GMP excreted). 
In general patients with cystic fibrosis excreted greater amounts of cyclic 
GMP than did normals. The most striking comparison was the ratio 
of cyclic AMP to cyclic GMP excreted which was 9.09 plus 
or minus 0.50 in all normal children and 4.41 plus or 
minus 0.32 in children with cystic fibrosis (P smaller than 0.001). 
