FINE STRUCTURE OF ENDOCRINE HINDGUT CELLS OF A LEPIDOPTERAN OSTRINIA NUBILALIS (HUBN)

Cells of the hindgut of the European corn borer, Ostrinia nubilalis, have two functions, namely, ion transport and secretion of a hormone called proctodone. In this species, proctodone is an essential requisite to the prepupal molt in conjunction with brain hormone synthesis. Apical infoldings and their associated mitochondria form mitochondrial pumps for ion transport from the gut lumen to the hemocoel. The endocrine function of the cells is evidenced by rhythmical formation and discharge of inclusion bodies every 8 hours. These measure from 800 Å to 3 μ. in diameter and vary in composition from bodies with whorled, myeloid content to inclusions with densely granular matrix. During the discharge phase, granular material appears in the basal infoldings and accumulates in large quantities underneath the basal lamina and in the hemocoelic clefts adjacent to the active cells. © 1969 Springer-Verlag.