Adrenal Gland in Wild Gray and Albino Rat

Abstract

The wild gray rat (Mus norvegicus) has larger adrenal glands for a given body weight or body length than does the tame albino rat (Mus norvegicus var. albinus). 1 In both varieties the females have larger adrenals than the males of equal size. In both sexes the adrenal glands of the adult gray rats weigh roughly twice as much as those of the albino rats. The work here reported was done to determine whether or not the proportion of the adrenal gland formed by the medullary (chromaffin) tissue was the same in both varieties or whether the larger glands of the gray rat consisted more largely of cortical cells.

The data for the albino rats were based on 27 female and 3 male adults. The material for the wild gray rats consisted of 9 females and 4 males caught near the laboratory and killed within 48 hours of capture. The glands were removed immediately after death, fixed, sectioned, stained, and the proportion of the glands formed by each part determined by measuring sections at every 100 micra.^2,3 The results are shown in Table I.

Table II is the comparison between 4 hypothetical animals of the same body weight to show the number of mg. of cortical and medullary tissue that would be found, according to Table I, in their adrenal glands. The data for the weight of the adrenal gland compared to body weight are taken from “The Rat”, 4 tables 148 and 206.