Retinoids in the bovine pineal gland.

Using high performance liquid chromatography, the level of retinoids was determined in the bovine pineal gland, retina, retinal pigment epithelium, cortical and subcortical brain tissues, skeletal muscle and the liver. Except the retina, the bovine pineal gland possesses levels of retinol and retinyl esters significantly higher than other brain tissues and muscle. However, unlike the retina, the bovine pineal gland does not possess a significant level of retinal, the chromophore for visual pigments in the retina. This finding suggests that the bovine pineal gland does not possess rhodopsin nor the property of phototransduction which has been fully established in the retina and pineal glands of lower vertebrates.