The ontogenetic evolution of cerebral renin and cathepsin D in the rat.

Renin and Cathepsin D activities were measured in different cerebral structures in foetuses, during the first month of life and in the adult rats. There are differences in the renin activity and cathepsin D activity both in the cerebral structures and during the ontogenetic development. While the cathepsin D was much increased in newly born animals as compared to foetuses and remained fairly constant during the rest of life, the cerebral renin activity was constantly decreasing toward adulthood. It was found that during the first two weeks after birth there is a renin activity increase in the cerebral cortex and hypothalamus, followed by a decrease and, at the end of the first month of life after birth, the values were equal to those found in adult animals. The same variations were found in the epiphysis between the 45th and 50th day after birth.