ACTHの副腎皮質に対する作用方式に関する形態学的観察

抄録

In present investigation, the maintenance test of ACTH was performed in order to elucidate the mode of action of this principle to the adrenal cortex as determined by the cytological observation. In the first group, the hypophysectomized male adult rats of Wistar strain were sacrificed at the 5th, 10th, 14th and 30th postoperative day as the control. The second group consisting of hypophysectomized rats was subcutaneously injected with ACTH 2.5mg/day/rat from the next day for 5, 10, 14, 30 days respectively. Each day-subgroup of hypophysectomized control consisted of 2-6 rats and hypophysectomized administered day-subgroup consisted of 2-3 rats. Materials removed immediately after the decapitation were fixed with Levi's solution and the paraffin sections obtained were stained with Heidenhain's iron hematoxylin. In preceding paper (1957) the author appointed the automacity of zona glomerulosa which may be responsible for the hyperactivity induced by the hypophysectomy, because of the fascicle formation and the accumulation of proteinic stainable granules within the cell-bodies. Present cytological alterations in the adrenal cortices following the hypophysectomy were reconcile in general with the descriptions in foregoing article, so a references is to be made to those data in it.
The adrenal gland weight could in no cases recover from the severe reduction following the hypophysectomy by means of the administration of ACTH ; further the decline in size of whole adrenal cortex was not reverted. However, it was learned that the salient histological feature showing the integral retraction from the atrophy of the adrenal cortex was apparent owing to our detail observations.
Five to 7 days after the withdrawal, zona glomerulosa elongated, in which there were a number of the glomeruli consisting of the numerous cells with obscure contour which were burdened with the abundant fat granules. By the administration the zone became to provide the fasciculata appearance whose cells included a majority of stainable granules instead of fat droplets. In the 10th, 14th and 30th postoperative day, the zone was subject to acquir the thorough fasciculata appearance and to obtain the broad extension amounting to 1/2 to 2/3 of the whole size of the adrenal cortex. This may be involved in a sign of active participation in secretory facility. The prolonged administra-tion of ACTH for corresponding days shortened conversely the width of zona glomerulosa, increased the number of stainable granules in its cells and made the glomeruli regenerated with the consequent unequivocal restitution beyond the normal level. The response in zona glomerulosa was inter-preted as the atrophy rather resembling caused by the chronic stress. We could neither recognize the clear-cut mitosis there nor the metamorphosis of fibrocytes in capsule to cortex cells.
The transitional zone constantly hypertrophied up to the 5th or 10th day, and thereafter it gradually declined in size and finally disappeared. The injection of ACTH for less than 10 days was in fact capable to make the inanition in this zone which had hypertrophied apparently, in spite of much supression in reacting capacity in advancing postoperative days more than 10 days.
The zona fasciculata was contracted without an exception in hypophysectomized control group ; its constituent cells fell into an atrophy ; the cell arrangement forming fasciculata was reliably irre-gullar ; most of them included abundant huge fat droplets. The administration failed to prevent the atrophy and subsequent disorder in cell distribution, notwithstanding the precise improvement so far as the internal structure of the cells is concerned. For example, the administration for 5 to 10 days increased conspicuously the number of the proteinic stainable granules. Since the augementation in number of them is consistent with the pattern of the adrenal cortex cells of the animals exposed by the persistent stressful agents,