Electron-microscopical investigations on adenohypophyses in sand rats (Psammomys obesus) before manifestation of diabetes mellitus).

The experiments have been carried out on the adenohypophyses of 20 sand rats (6 so called protodiabetic, 6 diabetic animals and 8 animals as control group). Of those cell types known in hypophyses alpha-(STH-)cells, prolactin (LTH-)cells, beta-(FSH-) cells, gamma-(LH-)cells and delta-(TSH-)cells were shown to exist in the hypophyses of the control group. -- The size of the granula of these cell types in the sand rats also corresponds to the values known from other rodents. A reduction of granular density could be noticed in the alpha-cells of the so called protodiabetic group as well as in the prolactin cells. The Golgi apparatus is prominent, and the mitochondria have grown and multiplied. The other cell types show no peculiarities. Changes were also found in the alpha- and prolactin cells of the diabetic group: The granula are diminished very much (more in the prolactin cells than in the alpha-cells), the ergastoplasm is much increased and has dense colonies of ribosomes. The Golgi apparatus is highly developed. These experiments prove ultrastructural changes in the cell types of the adenohypophyses not only in the state of a mellitus-like syndrome in sand rats but also during adaptation to laboratory holding of these animals. It is suggested that during adaptation to laboratory holding in a state of pronounced increase of body weight and in the state of a mellitus-like syndrome in sand rats the alpha-cells of the adenohypophyses are stimulated as well as the prolactin cells.