Abstract
Topics discussed include the .alpha.- and .beta.-cell as functional and structural units in metabolic regulation, glucoregulatory functions, extrapancreatic .alpha.-cells in the gastrointestinal tract, role of glucagon in the pathogenesis of diabetes, bihormonal (insulin and glucagon) abnormality hypothesis of the pathogenesis of the metabolic derangements of diabetes, therapeutic implications of this dual causation hypothesis for diabetics. [Humans, dogs and rats are discussed.].