First demonstration of porphyrins in the lacrimal glands: similarity to the Harderian gland.

The Harderian gland of rodents is the only known tissue with physiological occurrence of high concentrations of porphyrins. In this report we describe the occurrence of considerable concentrations of porphyrins in the extra-orbital and intra-orbital lacrimal glands of the male rat. Similarly as in the Harderian gland, HPLC analysis revealed protoporphyrin as being the prevalent porphyrin homologue in the lacrimal glands. The results may contribute to elucidation of the yet unknown function of the Harderian gland and its porphyrins.