[Lysosomes in the regulation of hormone secretion in the pituitary-adrenal gland axis].

The morphology and morphometrics of the lysosomes and associated structures were studied in hyposecreting corticotrophs and the cells of adrenal cortex zona fasciculata of the rats. Hyposecretion of this two types of the cells in the pituitary-adrenal gland axis was induced by dexamethasone administration. The lysosomes and other hydrolydase-positive structures were identified with CMPase cytochemistry. Quantitative evaluation of the lysosomes, crinophagic and autophagic vacuoles was carried out on the micrographs with MOP-Videoplan system. The results indicated that while inhibited secretion of ACTH accompanied by the increase of the crinophagic and autophagic vacuoles in corticotrophs, inhibited secretion of corticosterone accompanied by the increase of the autophagic vacuoles containing the mitochondria, ER which were steroid-synthesizing apparatus in adrenal cortex cells. The findings in the present study suggested that lysosomal degradation mechanism play a significant role in the regulation of hormone secretion in pituitary-adrenal gland axis. In addition to affirming earlier data that lysosomes took part in the regulation of protein secretion by crinophagy, the main conclusion derived from the present study was that lysosomes also functioned in the regulation of steroid secretion. By the way of autophagy i.e. sequesting and degrading a part of the steroid-synthesizing apparatus, the lysosomes rendered a mechanism in steroid-secreting cells to involve to the regulation process of hormone secretion. This might be an important and general rule as the crinophagy be to the protein-secreting cells.