Identification of [Met5]-enkephalin in developing, adult, and renewing tissues by reversed-phase high performance liquid chromatography and radioimmunoassay.

Extracts of adult corneal epithelium, and developing and adult cerebellum, aorta, and heart, from rats were evaluated for [Met5]-enkephalin. Samples were prepared by ultrafiltration and solid phase extraction with a C-18 Sep-pak, separated by reversed phase high-performance liquid chromatography, and analyzed by radioimmunoassay (RIA). This qualitative analysis revealed the presence of [Met5]-enkephalin in all tissues but the adult cerebellum. These results confirm and extend earlier reports that have used RIA or immunohistochemistry with regard to the presence of this opioid peptide in developing and renewing tissues, and indicate that [Met5]-enkephalin is indeed being recognized by immunological assays.