Choline acetyltransferase activity and weight of salivary glands in rats at different ages.

The choline acetyltranferase activity underwent marked changes during the life span: in the submaxillaries, the total enzyme activity increased 70-fold from birth up to the age of 3 months and it then remained constant throughout the rest of the observation period, i.e. up to 28-29 months; in the parotids, in contrast, it continued to rise beyond the age of 3 months and the highest value was reached at 24 months. The weights of the glands increased markedly up to 3 months. The gain in weight was less pronounced thereafter.