Defective Immunoreactive Insulin Secretion in the Acomys Cahirinus

In vivo studies of immunoreactive insulin (IRI) secretion and electron microscopic studies of pancreatic morphology have been performed in the spiny mouse, acomys cahirinus. A defective IRI release was demonstrated in response to glucose 1.0 gm./kg., arginine 200 mg./kg., glucagon 1 mg./kg., isoprenaline 20 μg./kg., aminophylline 240 mg./kg. and dibutyryl cyclic AMP 60 mg./kg., administered intraperitoneally when compared to normal Swiss white mice. The defect appeared to involve both phases of IRI release. Electron microscopic evidence supported the concept of defective IRI release in this species. Of particular interest was the frequent occurrence in B cells of autophagic vacuoles comparable to those described for other cells undergoing secretory arrest. It is suggested that the defect of IRI release involves some basic mechanism concerned with the transport of insulin out of the B cell.