Influence of secretagogues on volume and protein pattern in rabbit lacrimal fluid.

After certain tear proteins had been found to be markers of duct cell activity in the rabbit lacrimal gland, different secretagogues were tested to increase volume and protein secretion. Carbamyl-choline and the peptides eledoisin and vasoactive intestinal peptide (VIP) stimulated volume flux as well as secretion of the marker proteins indicating duct cell activation. Beta-adrenergic stimulation also increased secretion of a further tear protein. This might indicate that water is secreted by the duct cells. These are stimulated by the secretagogues mentioned above. Beta-adrenergic stimulation might in addition activate the acinar cell system.