Background: Apoptosis plays an important role in the morphogenesis of the renal papilla.

As a result, there was successive destruction of the mucosal barrier, medulla and cortex and necrosis of the renal papilla.

Hypothesis: Exogenously administered EGF in postnatal rat affects renal papilla growth with cell proliferation and apoptosis in the loop of Henle.

Conclusion: These findings suggest that exogenous EGF delays the development of loop of Henle in the renal papilla by reducing both apoptosis and cell proliferation.