Estimates of neurosecretory activity by an autoradiographic method in adult female Schistocerca gregaria (Forsk.)

Abstract

An autoradiographic method for estimating 35S-cysteine uptake by the neurosecretory system of Schistocerca gregaria is described. Slowly developing females reared without mature males have histologically “full” neurosecretory systems, and the turnover of 35S-cysteine is at a low level. Rapidly developing females, reared in the presence of mature males, and 21- to 23-day-old females in the middle of the second gonotropic cycle have histologically “empty” neurosecretory systems and a high turnover of 35S-cysteine. Newly emerged females have histologically “empty” neurosecretory systems, but a low turnover of 35S-cysteine. These experiments indicate that in slowly maturing female desert locusts, low rates of oocyte development are accompanied by a slow turnover of neurosecretory material, with synthesis exceeding release, resulting in the accumulation of neurosecretion within the corpora cardiaca. Rapid oocyte development is associated with a high turnover of neurosecretory material with synthesis and release occurring at approximately the same rate resulting in a system that is relatively devoid of stainable neurosecretory material. The newly emerged female has a low turnover of neurosecretion, but since production and release are in balance, or nearly so, the neurosecretory system remains relatively devoid of stainable material.