Morphological Studies on the Adreno-cortical Function of the Rat

Abstract

In order to study the morphological changes in the adreno-cortical functions in various conditions, normal and hypophysectomized male and female rats were used. The effects of various stressor and various steroid hormones on the adrenal gland were investigated histologically and histochemically. The functional relationships between the anterior pituitary and the adreno-cortical cells were also described.Chapter 1. Functional Morphology of normal male and female rats and the effects of gonadectomy on the ad renal cortex.In young rats, there were no histological and histochemical differences observed between the male and female adrenal cortex. But in adult rats, the adrenal of the female was larger than that of the male, and the sudanophilic granules were finer in the former than in the latter. In young rats, the transitional zone (sudanophobic zone) existed in both sexes, but in adult females, this zone was not observed. Following gonadectomy, the male adrenal weight was increased, but the female adrenal weight decreased slightly. The sexual dimorphism that is clearly observed in normal adult rats, became indistinct following gonadectomy. From these facts, the author also suggested that the adrenal function of adult female rats is greater than of adult male rats. And this functional dimorphism is probably due to endogenous estrogen in female rats.Generally, the sudanophilic granules of the adrenal cortex parallel Schiff reaction, Schultz reaction for cholesterol and the birefringent particles in the normal rat. But these histochemical findings did not always parallel the various functional conditions.Chapter 2. The relationship between adrenocortical function and the anterior pituitary. The author investigated the morphological and histochemical changes of the rat's adrenal cortex during adrenal hypersecretion following ACTH injection and during hyposecretion following hypophysectomy.1) The adrenal weight increased under prolonged administration of ACTH. And the adrenal weight seemed to be a good functional index in the prolonged experiments.2) The transitional zone (sudanopz hobe zone) always disappeared when the adrenal cortex was hyperfunctioning. On the other hand, this zone became broader during cortical hypofunction. From the appearance of this zone, one could know the adrenal cortical functional state.3) Using colchicine, the author observed mitotic activities of cortical cells during ACTH administration. The mitotic activities of the cortical cell were most frequently observed in the outer fasciculata and the glomerulosa.4) Following single injections of ACTH, the sudanophilic granules were almost depleted from the zona fasciculata and the zona reticularis, and the cells of the zona fasciculata showed hypertrophy, while the zona glomerulosa did not show any changes histochemically. This finding may support Deane's concept (zonal theory). But with prolonged injection of large amounts of ACTH, the sudanophilic granules of the zona glomerulosa were also depleted, and the glomerulosa cells were also hypertrophied. From this experimental result and our other observations, the author made the following conclusions. During overwhelming cortical hypersecretion, the demand for fascicular function is increased and the cells of the zona glomerulosa are transformed into fasciculata cells. Therefore the zona glomerulosa and the zona fasciculata have the same cells of origin, and are not independent cells. Chapter 3. Morphological changes of the adrenal cortex under various stressfull conditions. The histological and histochemical changes of the adrenal cortex under stress generally seemed to be non-specific reactions and similar to the reaction following ACTH injection. But some of the stressors caused peculiar changes in the adrenal cortex. After prolonged administration of adrenalin, many exhaustive vacuoles were seen in the zona fasciculata.