The fine structure of the corpus allatum of the sexually mature male of the desert locust

Abstract

An electron microscopic study of the corpus allatum of the mature adult male desert locust, Schistocerca gregaria, was made and it indicated the structural basis for the mode of secretion of the corpus allatum hormone. The gland is dominated by the smooth-surfaced endoplasmic reticulum; and its hormonal activity is correlated with the development of this membrane system. In the hormonally active gland, the smooth endoplasmic reticulum establishes an extensive network, apparently initially formed in the Golgi region. The vesicles from the latter progressively enlarge, and eventually empty onto the membrane, which not only surrounds the gland but also penetrates into the gland in considerable amounts. The ultrastructural localization of the corpus allatum hormone cannot be stated with certainty, but it is thought that the smooth endoplasmic reticulum is intimately associated with the biosynthesis of the corpus allatum hormone, perhaps initially packaged by the Golgi apparatus. Neurosecretory axons from the nervus corporis allati 1 make an intimate contact with the gland cells. No such neurosecretory axons are found in the nervus corporis allati 2 connecting the gland to the suboesophageal ganglion. Exchange of materials seems to occur across junctional regions, which often have very convoluted membranes and where microtubules appear to be concentrated.