The renal kallikrein-kinin system in Brattleboro rats with hereditary hypothalamic diabetes insipidus. Missing relationship between antidiuretic hormone and the renal kallikrein-kinin system.

The activity of the renal kallikrein-kinin system was investigated in male Brattleboro rats homozygous for hypothalamic diabetes insipidus (DI); Long-Evans rats (LE) were taken as controls. In the rats with DI, urinary kallikrein excretion was lower (P less than 0.05) than in the LE rats. However, when related to total renal mass or to body weight, there was no difference between the two strains. Kallikrein activity in the renal cortex was similar in the Brattleboro and the LE rats. Antidiuretic hormone (vasopressin tannate) in a dose of 100 mU given once daily for 3 days had no effect on urinary kallikrein excretion in either of the strains. Water deprivation for 24 h resulted, also in both strains, in a similar reduction in urinary kallikrein excretion. The renal kallikrein-kinin system of LE rats and that of DI rats does not principally differ in basic activity, nor in response to the administration of vasopressin, nor to water deprivation.