[Postnatal development of renal concentrating ability in a desert rodent, Jaculus orientalis]

Postnatal development of renal function was studied in newborn Jerboa from six weeks after birth. The results showed that the renal capacity of urine-concentration was more or less analogous to that of the adult, starting 15 weeks after birth when the animal reached a body weight of about 70 to 90 g. From the 13th week onwards, the U/P ratio of the osmolality in function of age, increases when the urinary debit decreases. The osmotic-clearance and the free water-clearance will show stability 15 weeks after birth.