The pigmentotropic hormone [His(7)]-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 d esert locust, Schistocerca gregaria, as the dark colour inducing neurohormo ne. Here, we investigate whether [His(7)]-corazonin occurs in the brain-CC axis of a Schistocerca albino strain. From data obtained by immunocytochemi stry, injection experiments, chromatographic and mass spectrometric analysi s 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 une quivocally demonstrated by sequencing the [His(7)]-corazonin-immunoreactive factor in albino Schistocerca brain-CC extracts with ESI-Qq-oa-TOF mass sp ectrometry. Albinism in this strain is hence not caused by the deficiency o f authentic [His(7)]-corazonin in the: brain-CC axis, nor by defects in rel ease. Conversely to L. migratoria albinos, injection of [His(7)]-corazonin failed to induce dark pigmentation in Schistocerca albinos. Therefore, albi nism in the investigated Schistocerca strain is likely to be situated at th e level of the receptor. signal transduction mechanisms or of pigment biosy nthesis. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.