Renography in the foetal and newborn lamb.

Hippuran renography indicates kidney function as reflected in a substance handled mainly by the tubules. The working conditions of the kidneys undergo a fundamental change at birth with the cessation of placenta circulation, and these organs become responsible for waste elimination. 131I-hippuran renography was performed on foetal and newborn lambs using a gamma camera and a computer. The intervals of the maximum- and half-time renal activity were determined. These decreased by a half from mean foetal value of Tm=7 mi and T12=19 min in 1 to 1.5 days and reached the full-grown level in 2 to 5 weeks. No sudden change occurred as a result of the first breath.