MULTIPLE MEMBERS OF THE LEUCOKININ NEUROPEPTIDE FAMILY ARE PRESENT INCEREBRAL AND ABDOMINAL NEUROHEMAL ORGANS IN THE COCKROACH LEUCOPHAEA-MADERAE

Two neurohemal organs of the cockroach Leucophaea maderae, the corpora cardiaca and the lateral heart nerve are known to contain leucokinin immunoreactive material, We examined the corpora cardiaca and the late ral heart nerve to establish whether these neurohemal organs store all 8 known leucokinin isoforms or if the leucokinins have a differential distribution, Extracts of corpora cardiaca and abdominal hearts with attached lateral heart nerve were separated on reversed phase high per formance liquid chromatography (rpHPLC), then tested for leucokinin im munoreactivity by a radioimmunoassay (RIA) able to detect all 8 leucok inin isoforms, Extracts from brain and optic lobes were also separated and assayed in the RIA, Synthetic leucokinin 1-8 were subjected to rp HPLC and their different retention times established by RIA for refere nce, Leucokinin immunoreactive material originating from the corpora c ardiaca and lateral heart nerves eluted in fractions corresponding to those of the synthetic leucokinin 1-8. In this study we have thus demo nstrated that probably all 8 leucokinin isoforms are stored in the cor pora cardiaca and the lateral heart nerve. These observations suggest that all 8 leucokinins are likely to be released as neurohormones into the circulation.