副腎 4. 各種の副腎皮質阻害剤を投与したさいの副腎皮質と髄質の相関について

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Though the work of Wurtman & Axelrod (1965, 1966) on the effect of dexamethasone and hypophysectomy on the activity of PNMT in the rat adrenal, that corticosterone (CS) induces the formation of PNMT seems to be widely accepted, it remains a few unsettled problems. Results obtained were as follows; 1) In report on the effect of immobilization (immobil.) upon adrenal cortex and medulla of the rat (Okamoto, 1970), his conclusion was that the procedure of immobil. resulted in a marked increase of the activity of these both tissues as reflected in a persistent elevation of plasma CS and a significant decrease of adrenal catecholamines (CA) followed by a overcompensated period due to the increased CA synthesis. In contrast with the sham-operated rat, no remarkable change of adrenal CA was observed in the coeliac ganglionectomized rat during or on the period of setting free from immobilization. The results are interpreted to indicate that the effect of immobil. on adrenal CA is mediated by an elevated sympathetic activity and succeeded by the increased CA synthesis as the result of the decreased endproduct inhibition. 2) The single administration of such adrenocortical blockers as dexamethasone, 3-methylcholantrane, 7, 12-dimethylbenz (α) anthracene (DMBA) and metopyrone did not induce a significant change of suprarenal adrenaline (AD) content except for relatively decreased AD content in hypophysectomized rats. When the procedure of immobil. was added to the rats pretreated with these adrenocortical blockers, the repletions of suprarenal AD which is expected to occur after setting free from immobil., were remarkedly suppressed in all groups which were administered with such drugs as well as in the hypophysectomized rats. These findings indicate that Wurtman & Axelrod's theory is almost valid in the adrenal gland of the non-hypophysectomized rat which was acutely inhibited by several adrenocortical blockers. 3) But the tendency of the repletion of suprarenal AD content was still observed after the restraint of the rat which was pretreated with any tested adrenocortical blocker as well as of the hypophysectomized rat. It is logical to assume that the methylation of NA in the adrenal medulla may be kept in reserve, even if the aboundant supply of CS from the adrenal cortex to the medulla is acutely interrupted. 4) In spite of such intensive stimulus as producing a marked elevation of plasma CS, the effect of the immobil. on suprarenal AD content of the rat pretreated with DMBA, was diminished with coeliac ganglionectomy. These facts suggest that further stimulation of adrenocortical output does not increase AD synthesis. 5) The histological analysis of "adrenocorticlolysis" due to the treatment with DMBA revealed the massive destruction of the sinusoid in the rat adrenal cortex which is assumed to supply a high concentration of CS from the cortex to the medulla. From these results, it is necessary for the methylation of NA on the adrenal medulla that there is not any circulatory disturbance from the adrenal cortex to the adrenal medulla. 6) The decreased rate of the suprarenal AD content due to CA synthesis blocker was more accelerated in the DMBA pre-treated rats than in the non-treated rats. But no significant difference between the dexamethasone (20 γ/rat/day) pretreated rats and the non-treated rats was observed as concerned with the decreased rate of the suprarenal AD content due to CA synthesis blocker. 7) The prodceure of the immobilization which is able to activate intensively both the adrenal cortex and medulla is a useful tool for the study of the intimate correlation between the adrenal cortex and the adrenal medulla.
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副腎 4. 各種の副腎皮質阻害剤を投与したさいの副腎皮質と髄質の相関について

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