Clonidine decreases rat urine kallikrein excretion by alpha-adrenergic receptor stimulation

In normal conscious female Sprague-Dawley rats, clonidine dose-dependently (10-300 micrograms/kg) decreased urine kallikrein excretion to approximately 40% of the control value. The effect of clonidine on urine enzyme excretion was inversely related to diuresis-natriuresis. Phenoxybenzamine (1 mg/kg) or phentolamine (10 mg/kg) antagonized the effect of clonidine on urine enzyme excretion. Consequently, rat urine kallikrein excretion might be reduced when alpha-adrenergic receptors are stimulated by clonidine.