Kidney development in newborn lambs: Response to water load and antidiuretic hormone (ADH)

Abstract

Six newborn female lambs were maintained on a formula similar to normal ewe's milk and five on a high protein diet for up to 7 weeks. From the earliest postnatal days a series of urine and blood samples was collected from each lamb twice weekly. The first series of samples was obtained after oral water loading and a second series was collected after ADH administration following an identical water load. Diuretic response to oral water load was as pronounced during the early postnatal days as at 7 weeks. The neonatal ovine kidney was responsive to ADH: ADH administration caused a significant alteration in the diuretic pattern induced by oral water load in the earliest postnatal period studies. There was a marked increase in solute excretion following ADH administration in all lambs. Kidneys of lambs maintained on the high protein diet showed enhanced solute free water reabsorption but also had increased excretion of sodium and potassium following ADH administration.