The rabbit lacrimal gland in vitamin A deficiency

To investigate the morphology, ultrastructure, and protein secretion of the vitamin A-deficient rabbit lacrimal gland. The lacrimal glands of vitamin A-deficient rabbits and age-matched controls were fixed, processed by standard methods, and examined by light and transmission electron microscopy. Protein secreted by the lacrimal gland was analyzed using gel filtration chromatography and electrophoresis. By light microscopy, the glands of experimental and control rabbits were indistinguishable. Electron microscopy showed little effect of vitamin A deficiency on the lacrimal acini, although occasional pyknotic nuclei were observed. The intralobular ductal epithelium was unaffected. Protein concentration and composition were essentially unchanged in lacrimal gland fluid of vitamin A-deficient rabbits compared to controls. The rabbit lacrimal gland is minimally affected by vitamin A deficiency, suggesting species differences between rabbits and rats in the vitamin A requirements of the lacrimal gland. Normal lacrimal gland structure and function in vitamin A deficiency allow for the prompt secretion of retinol on the restoration of vitamin A to the diet.