[The subcapsular blastema of the adrenal cortex of the swine after continuous long-term infusion of exogenous ACTH].

After long time application of homologous ACTH the morphokinesis of the adrenal cortex of the pig was investigated experimentally. Following results were obtained: 1. In view of the controls the absolute and relative weight of the adrenals is raised considerably. 2. The progressive transformation is followed by the disappearance of the zonal structure of the adrenal cortex, and the parenchyma get the picture of fasciculata cells generally. 3. Nearly exclusive the zona fasciculata consists of great, pale activated spongiocytes with 2 nucleoli frequently. Topochemically glycogen and the lipids are inconstant, however the histochemical activity of succinodehydrogenase, lactate dehydrogenase, acid and alkaline phosphatase are considerable raised in regard of the controls. 4. The zona fasciculata contains degenerated cells isolated only. Signs of extensive regressive changes are not present. 5. The zona glomerulosa is dissolving or eliminating respectively. The consequences for the synthesis of the adrenal steroid hormones are discussed. 6. A large, spongy subcapsular blastema with several cell layers and a rich capillary network develop between the fibrous capsula of the adrenal and the zona fasiculata. The fasciculata cells are the direct continuation of the subcapsular blastema. The blastema contains neither glycogen nor lipids and histochemical activities of the enzymes are absent, too. The significance of the subcapsular blastema for the morphological and functional adaptation of the adrenal cortex in stress are discussed. Under the conditions of the closed hypothalamo-hypophyseal-adrenal control system the new origin of cells (hyperplasia) is not significant for the morphokinetic adaptive reactions of the adrenal cortex. Rather the subcapsular blastema represents a reserve area which after the destruction of the endocrine parenchyma through specific pathogens the organism enabled to the regeneration of the adrenal cortex.