The pigmentotropic hormone [His7]-corazonin, absent in a Locusta migratoria albino strain, occurs in an albino strain of Schistocerca gregaria

[His(7)]-corazonin has recently been identified in the corpora cardiaca (CC) of two locust species, the migratory locust, Locusta migratoria and the desert locust, Schistocerca gregaria, as the dark colour inducing neurohormone. Here, we investigate whether [His(7)]-corazonin occurs in the brain-CC axis of a Schistocerca albino strain. From data obtained by immunocytochemistry, injection experiments, chromatographic and mass spectrometric analysis of brain and CC tissues, it could be concluded that an albino strain of S. gregaria from Denmark contains authentic [His(7)]-corazonin. This was unequivocally demonstrated by sequencing the [His(7)]-corazonin-immunoreactive factor in albino Schistocerca brain-CC extracts with ESI-Qq-oa-TOF mass spectrometry. Albinism in this strain is hence not caused by the deficiency of authentic [His(7)]-corazonin in the: brain-CC axis, nor by defects in release. Conversely to L. migratoria albinos, injection of [His(7)]-corazonin failed to induce dark pigmentation in Schistocerca albinos. Therefore, albinism in the investigated Schistocerca strain is likely to be situated at the level of the receptor. signal transduction mechanisms or of pigment biosynthesis. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.