title: Some histological and histochemical studies of the pancreas of the Brasilian sloth, Bradypus tridactylus.
abstract: The histological and histochemical study of the pancreas of the three-toed sloth, Bradypus tridactylus, demonstrated that with the methods employed the pancreatic islets are apparently formed by A cells exclusively. Two different types of argyrophilic cells were noticed in the exocrine secretory units when Grimelius' method was used. The methods for the demonstration of D cells showed negative results. Aldehyde fuchsin-positive granules were only noticed at the apex of the exocrine pancreatic cells. These results are discussed in relation to current hypotheses concerning the evolution of insulin secretion mechanisms.
mesh_terms: D000818:Animals; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D007515:Islets of Langerhans / Q000166:cytology / Q000648:ultrastructure; D010179:Pancreas / Q000166:cytology*; D012896:Sloths / Q000033:anatomy & histology*; D013194:Staining and Labeling; D004490:Xenarthra / Q000033:anatomy & histology*