Effect of ageing on cyclic AMP output by renal medullary cells in response to arginine vasopressin in vitro in C57BL/Icrfat mice

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Abstract
The effect of age on the cyclic AMP (cAMP) response to increases in the concentration of arginine vasopressin in the presence of isobutyl methylxanthine (100 μmol/l) was studied in an in-vitro renal cell suspension prepared from C57BL/Icrfat mice at 6, 12, 18, 24, 29 and 35 months of age. Comparison of the response of the preparation to vasopressin, calcitonin and parathyroid hormone suggested that it was enriched with renal medullary cells. Basal cAMP output was similar throughout but the threshold dose of vasopressin increased from 1 × 10−11 mol/l (6, 12 and 18 months of age) to 1 × 10−10 mol/l (24, 29 and 35 months of age). The dose–response curve in 35-month-old mice was shifted to the right with the concentration of vasopressin required to give half maximal cAMP increased from 9·4 ± 0·37 × 10−11 mol/l (6 months) to 3·5±1·6 × 10−10 mol/l (35 months). Maximum cAMP output at 1 × 10 −9 mol/l was also reduced in the same animals (stimulated:basal ratio, 51·22±19·12 at 6 months; 11·50 ± 6·02 at 35 months). The results suggest that the lack of renal response to vasopressin in terms of cAMP metabolism may play a role in the well-documented age-related decline in urine-concentrating ability in experimental animals and elderly people. J. Endocr. (1984) 103, 133–139