AN APPROACH TO THE QUANTITATIVE HISTOCHEMISTRY OF THE A-CELLS IN THE PANCREATIC ISLETS

Abstract
Our present knowledge of the quantitative histochemistry of the pancreas is mainly related to the enzymatic properties of the exocrine parenchyma and the B-cells. Appropriate analyses of A-cells require their isolations, which can be accomplished in animals with different islet cells located in separate groups. In fresh frozen sections of the pancreas from ducks groups of A- and B-cells were recognized by darkfield microscopy combined with ordinary microscopic examination after fixation and staining. Each adjacent section was lyophilized and separate samples of acini, A-and B-cells were dissected by free hand. Using quantitative microchemical techniques malic dehydrogenase, lactic dehydrogenase and glutamic-oxaloacetic transaminase activities were measured. The enzymatic distribution found between samples of B-cells and acini was in accordance with earlier findings in mammals, as B-cells showed higher activities except for lactic dehydrogenase. The A-cells differed from the B-cells by lower activities of malic dehydrogenase and glutamic-oxaloacetic transaminase and from the acini by lower activities of lactic dehydrogenase.