STIMULATION OF CORPORA ALLATA BY EXTRACT FROM NEUROENDOCRINE COMPLEX - COMPARISON OF REPRODUCING AND DIAPAUSING PYRRHOCORIS-APTERUS (HETEROPTERA, PYRRHOCORIDAE)

The effect of extracts from neuroendocrine complexes of brain-suboesop hageal ganglion-corpora cardiaca-corpus allatum (NEC) on synthetic act ivity of corpora allata (CA) in vitro was investigated by a radiochemi cal assay in Pyrrhocoris apterus. NEC extracts from short-day (diapaus ing) females and long-day (active) females and males were compared. NE C extracts from both short-day and long-day insects stimulated synthet ic activity of the CA from long-day females. The CA from shea-day fema les were refractory to stimulation. The stimulating activity of the NE C extract was retained after removal of proteins using 10,000-molecula r weight limit centrifugal ultrafiltration, but was destroyed by treat ment with proteinase K. Therefore, the stimulating factor appears to b e a peptide. The culture medium containing a mixture of synthetic prod ucts of the CA was extracted by hexane and subjected to TLC analysis. It was revealed that the NEC extract stimulated synthesis of a product from radiolabelled methionine which elutes on TLC in the same positio n as the major product of the CA of four other heteropteran species.