The biology of the prothoracicotropic hormone peptidergic neurons in an insect

Abstract

SYNOPSIS. The prothoracicotropic hormone and the cerebral peptidergic neurons that produce it have traditionally been thought to have the singular function of acting as a primary effector of insect postembryonic development. Recent investigations of this neuroendocrine axis in the tobacco hornworm, Manduca sexta, are leading to a new view that these peptidergic neurons and their peptide phenotypes may be multifunctional. They may act in different ways depending upon the animal's developmental stage and site of phenotype release. The possibility for this functional diversity of the prothoracicotropic hormone is possibly even greater due to multiple neuronal sites of peptide expression within the central nervous system. Similarly, the L-NSC III may have more functions due to the expression of multiple peptide phenotypes. The data, thus far, have not enabled us to identify additional physiological roles for the peptide, but they have provided insight into the experimental approaches that might be effective in resolving these functions. © 1993 by the American Society of Zoologists.