Endocrine pancreatic cells of postnatal "diabetes" (db) mice in cell culture.

Ultrastructural characteristics as well as secretory and biosynthetic behavior of monolayer pancreatic cell cultures established from 4-day-old C57BL/KsJ misty diabetic (m db/ m db) mice have been studied in comparison to normal littermate controls. Hypersecretion of glucagon by α-cells from BL/Ks misty diabetic mice after 2 days in vitro was found to precede any hyperfunction of the insulin-secreting β-cells. The increased level of glucagon-release in BL/Ks cell cultures from diabetic mice was accompanied by a greatly enhanced level of incorporation of [3H] tryptophan into glucagon-like molecules whose specific radioactivity was up to 15-fold higher than that observed in cultures from genetic controls. The finding of an α-cell dysfunction in cultures established from preweaning diabetic BL/Ks mice suggests that glucagon could play an early role in shaping the events that culminate in the expression of frank diabetes in this inbred strain.