Ultrastructure and morphometry of ACTH-producing cell in the rat anterior pituitary gland stimulated by lysin-vasopressin and prostaglandin E1.

The aim of this study was to investigate the qualitative and quantitative changes of ACTH-cells in the rat after application of a specific and a non-specific stimulus. A CRF-analog (lysin-vasopressin) and a prostaglandin (prostaglandin E1) were used. 40 rats were injected lysin-vasopressin or prostaglandin E1, respectively, for 4 weeks. The pituitary glands were investigated by means of light microscopy, electron microscopy and morphometry. Activation of the ACTH-cells could be observed after use of both substances, the effect of lysin-vasopressin being more intense than that of prostaglandin E1. Enlargement of the nucleus, the cytoplasm and the organelles involved in hormone-production and -transport were found and verified by morphometry. Additionally an increase in number of the cells could be demonstrated. Prostaglandin influenced not only ACTH-cells, but also other cells of the anterior pituitary.