EFFECTS OF CHRONIC ETHANOL ADMINISTRATION ON THE GLUCAGON-PRODUCING A-CELLS IN RAT ENDOCRINE PANCREAS - A MORPHOMETRIC AND FINE-STRUCTURAL STUDY

The present study describes optical and ultrastructural features of gl ucagon-producing A-cells in the male Wistar strain rat after chronic ( 4 months) alcoholism where nutriition was well controlled. Male Wistar rats were given ethanol to provide 23% of the total energy (group E), while starch replaced ethanol isocalorically in controls (group C). T he ''point counting'' technic was used to evaluate morphometric/stereo logical parameters on the islets and glucagon-producing A-cells. Immun ohistochemically detected A-cells showed a ring like distribution in b oth groups of rats. At the ultrastructural level, most of the A-cells resembled those in the control, but a small number of A-cells were cha nged with deep invagination of the nuclear envelope and condenzed chro matin. The total number of endocrine cells, both per islet and per mm( 2) of islet was increased in the ethanol-treated rats. Glucagon-produc ing A-, somatostatin-producing D-, and pancreatic polypeptide producin g PP-cells were increased, while insulin-producing B-cells were decrea sed. Stereological investigation at the ultrastructural level showed t hat the profile area of the whole A-cell, cytoplasm, Golgi system and gER was diminished, and that of mitochondria increased. Volume density of the nuclei and Golgy system was decreased, while cytoplasm granule s and mitochondria were more numerous the former because of a greater number of mature granules. The mean diametar of the granules was signi ficantly reduced in ethanol treated rats. All the results obtained ind icated hypoactivity of A-cells.