Author:

Abstract:

Members of the insulin superfamily are not restricted to vertebrates, but have also been identified in invertebrate species in which they are termed 'insulin-related peptides' (IRPs) or 'insulin-like peptides' (ILPs). By means of a high-performance liquid chromatography (HPLC)-based purification strategy an IRP was isolated from Schistcocerca gregaria corpora cardiaca (CC) extracts and was termed Scg-IRP. Subsequent cloning and sequencing of the corresponding cDNA revealed that the encoded Scg-IRP precursor displays the structural organization that is typical for members of the insulin superfamily. Moreover, immunocytochemistry on brain tissue sections demonstrated the presence of Scg-IRP in median neurosecretory cells of the pars intercerebralis and their projections towards the storage part of the CC. Quantitative real-time RT-PCR studies revealed the presence of Scg-IRP transcripts in a variety of tissues, including nervous tissue and fat body. Furthermore, these transcripts showed a tissue- and phase-dependent, temporal regulation during the reproductive cycle of adult males and females. In the same context, we are studying the role of Scg-IRP and its signalling pathway in the physiology of locust reproduction.