Harderoporphyrin: a misnomer

More than 30 years ago it was reported that rodent Harderian glands contained a tricarboxylic acid porphyrin, which the authors named Harderoporphyrin. The recent finding in rat Harderian glands of the porphyrin glycoconjugate, protoporphyrin-1-O-acyl-beta-xyloside as a major component led to scrutiny of earlier publications. It became apparent that the results were flawed and that the conclusions were unsustainable. The procedural artefacts which led to the errors are discussed and their bases are demonstrated experimentally. Harderoporphyrin as originally defined never existed.