Sex hormone regulation of tear lipocalin in the rabbit lacrimal gland.

Tear lipocalin (TL) (approximately 18 kDa), a member of the lipocalin superfamily, has been identified as one of the major proteins present in rabbit lacrimal fluid. The concentration of TL has been found to be decreased in the tears of patients with dry eye disease. Lacrimal gland insufficiency, one of the major causes of dry eye disease, is known to affect mainly postmenopausal women, where there is a significant decrease in the production of androgen and estrogen.

Estrogen up-regulation of metalloproteinase-2 and -9 expression in rabbit lacrimal glands.

Increased levels of the matrix metalloproteinases (MMPs)-2 and -9 have been found in tear fluids of patients with dry eye disease, suggesting that these MMPs may be implicated in the pathogenesis of this disease. One of the main causes of dry eye disease is lacrimal gland insufficiency. However, the contribution of the lacrimal gland (LG) to the expression and production of MMP-2 and MMP-9 in tears is not known.