Cyclic nucleotide metabolism in compensatory renal hypertrophy and neonatal kidney growth

Cyclic nucleotide metabolism was investigated in growing kidneys of rats during compensatory hypertrophy and during neonatal development. After unilateral nephrectomy a mild and short-lasting decrease in cyclic 3':5" adenosine monophosphate (cAMP) was observed in the hypertrophying kidney. In contrast, cyclic 3':5' guanosine monophosphate (cGMP) showed a sharp decline to 20% of control at 15 min and a rapid rise to 200-300% above base-line at 1-72 hr. The alterations in renal tissue levels of cGMP were associated with parallel changes in the soluble, 100,000 X g supernatant guanylate cyclase activity [GTP pyrophosphate-lyase (cyclizing): EC 4.6.1.2]. No change was observed in total cGMP phosphodiesterase (3':5'-cyclic-nucleotide 5'-nucleotidohydrolase; EC 3.1.4.17). In the rapidly growing kidney of newborn rats cAMP levels were 983 +/- 65 and 833 +/- 42 pmol/g of kidney at 4 and 7 days after birth, and increased to adult levels (1518 +/- 57 pmol/g) at 21 days whereas cGMP levels were 59.8 +/- 6.8 and 92.5 +/- 13.9 pmol/g at 4 and 7 days and decreased to adult levels (36 +/- 1.5) at 21 days. The results indicate that compensatory renal hypertrophy and neonatal kidney growth are associated with changes in cAMP and cGMP metabolism.