Effect of age of the rat on induction of acetylcholinesterase of the brain by 17β-estradiol

Abstract

1. 1. The activity of acetylcholinesterase and its induction by estradiol in the cerebral hemisphere and cerebellum of immature (9-), adult (29-) and old (65-week) female rats were studied to understand the mechanism of aging. 2. 2. The activity of the enzyme of the cerebral hemisphere is highest in the immature rat and decreases thereafter. There is no such change in its activity in the cerebellum as a function of age. 3. 3. Estradiol increases the activity of the enzyme in the cerebral hemisphere and cerebellum of normal immature and adult rats. The magnitude of stimulation is higher in immature rats. Estradiol induces the enzyme in both the organs of ovariectomized immature and adult rats, but not of old rats. The induction of the enzyme by the hormone is actinomycin D sensitive. 4. 4. Kinetic, electrophoretic and immunological studies on the partially purified enzyme indicate the presence of a single molecular species of acetylcholinesterase at all the ages studied.