Determination of bovine retinal melatonin with HPLC-EC.

Unlabelled: Bovine retinae, devoid of pigment epithelium, were assayed for endogenous melatonin using high-performance liquid chromatography with electrochemical detection (HPLC-EC). A method of extracting the more polar biogenic amines and metabolites was employed, allowing for direct injection of retinal supernatants into the chromatographic column.

The Results: 1) confirm the presence of melatonin in the bovine retina; 2) provide a "benchmark" of 3.01 ng/retina for normal adult retinae collected during photophase; and 3) indicate that HPLC-EC represents an adequately sensitive instrument for the detection and quantification of melatonin in a single bovine retina.