Immunohistochemical identification of growth hormone-releasing factor-like material in the nervous system of an insect, Aeshna cyanea (Odonata).

Cells immunoreactive to antibodies raised against human pancreatic growth hormone releasing factor 1-44-NH2 (hp GRF) were detected in the brain and the suboesophageal ganglion of an insect. The presence of immunoreactive deposits within the insect neurohaemal organ, the corpora cardiaca and within the nervi corporis cardiaci which, at least, transfers part of the neurosecretory products of the brain to the corpora cardiaca, may indicate the participation of GRF-like substance in some neurohormonal function (s) in addition to having probably a neurotransmitter role within the nervous system.