Diversity of prolactin systems in the insect Leucophaea maderae: use of antiserum polyclonality for immunocytochemical detection of neuropeptide heterogeneity.

The presence of prolactin-like neuropeptides was demonstrated immunocytochemically in the brain and affiliated neuroendocrine structures of the insect Leucophaea maderae. Use of the unlabelled peroxidase-antiperoxidase method of Sternberger revealed a rather widespread and differential distribution of reaction products resembling human (hPRL) and ovine (oPRL) prolactin. Tests with antirat PRL antibody were negative. The specificity of the antibodies used was established by liquid-phase absorptions and confirmed in tissue control systems. In L. maderae, anti-oPRL identifies part of an oPRL-like molecule different from human and rat PRL. Anti-hPRL reveals part of a human and ovine PRL-like molecule different from rat prolactin. These results indicate the occurrence, in the nervous tissue of one insect species, of at least two types of prolactin-like molecules.