Pineal glands of immature rats: Rise and fall inN-Acetyltransferase activityin vitro

Abstract

N‐acetyltransferase activity in the pineal glands of immature rats (12‐14 days old) shows a spontaneous rise and fall when the glands are placed in organ culture. The peak of the 28‐fold change occurs 5–16 hr after the cultures are initiated. This observation can be interpreted in two ways: (1) the pup pineal gland is responding to norepinephrine released when nerve endings degenerate in culture, or (2) the pup pineal gland has an innate ability which is responsible. Whatever the mechanism, the phenomenon is associated with the development of pineal gland function since pineal glands of adult rats do not show a spontaneous rise and fall in identical experiments.