CELLULAR COLOCALIZATION OF DIURETIC PEPTIDES IN LOCUSTS - A POTENT CONTROL MECHANISM

Locust abdominal ganglia are shown to colocalize Locusta-diuretic pept ide-, leucokinin I-, and lysine vasopressin-like immunoreactivity in p osterior lateral neurosecretory cells. Extracts of abdominal ganglia w ere partially purified by RP-HPLC then dot immunoassay screened with t he same antisera used for immunocytochemistry. Locusta-diuretic peptid e-like immunoreactive material coeluted with synthetic Locusta-diureti c peptide, and leucokinin-like immunoreactive material coeluted with l ocustakinin. Lysine vasopressin-like material eluted in fractions that also showed Locusta-diuretic peptide and leucokinin I immunoreactivit y. The diuretic activity of synthetic Locusta-diuretic peptide and loc ustakinin is demonstrated, and they are shown to act at least additive ly to promote Malpighian tubule fluid secretion. The immunoreactive ne urosecretory cells are assumed to express at least these two peptides, and a model for promoting fluid secretion is proposed.