Brain Excitability in Relation to Age and Hypophysectomy

Abstract

Summary

An investigation was carried out in Sprague-Dawley, male rats to determine relationship of total body, brain, adrenal, and liver weights, and age on EST in intact growing, and in early and late hypophysectomized rats. 1. EST is progressively increased in relation to age in intact growing, and in early and late hypophysectomized rats. 2. Statistical analysis of values obtained shows that regression coefficients of Age vs. EST of intact growing and of late hypophysectomized rats are almost identical, whereas those of early hypophysectomized rats are lower. It is possible that early hypophysectomized rats become more sensitive to the stimulus than intact or late hypophysectomized animals. 3. The conclusion is reached that other variables, particularly age, have to be considered in seeking information of the effect of deficiency state itself on EST, or more generally on central nervous system sensitivity. On this basis, many previous conclusions require revision.