[The effect of early postnatal sympathectomy on kidney concentrating function in rats].

Renal concentrating function has been studied in adult Wistar rats after injections of guanethidine (25 mg/kg) or physiological saline (control) to 1-30 days old rat puppies. Urine osmolality in 30- and 60-day guanethidine-treated rats after test injections of ADH (pituitrin, 5 microU/g) or after water deprivation for 24 h was higher than in control animals. Concentrations of potassium, sodium, and urea were practically equal in all the zones of renal tissue from both groups of rats. The data obtained indicate that renal efferent nerves do not affect significantly the formation of renal concentrating function. It is suggested that elimination of influences of alpha 2-adrenoreceptors, which are antagonistic to the effect of ADH, accounts for the observed increase in antidiuretic effect.