Androgen support of lacrimal gland function

The effects of dihydrotestosterone (DHT) (1 mg/kg) on biochemical parameters related to lacrimal secretion, basal tear flow rate, and pilocarpine-stimulated lacrimal gland fluid secretion, in mature ovariectomized rabbits were studied. The effects of the synthetic estrogen diethylstilbestrol (DES) (100 micrograms/kg), on lacrimal gland biochemical parameters in normal mature female rabbits was also studied. Ovariectomy decreased the total serum levels of testosterone (T) by 88.5% and androstenedione by 35.9%, without changing the levels of dehydroepiandrosterone (DHEA) of its sulfate. Ovariectomy caused a significant regression of the lacrimal glands, decreasing total DNA by 35%, and total protein by 22%. DHT treatment of ovariectomized animals prevented lacrimal gland regression, increasing total gland DNA (31%) and total protein (18%). DHT treatment also increases Na+, K(+)-ATPase activity (29%) and beta-adrenergic receptor binding sites (23%) compared to the ovariectomized group. DHT increased pilocarpine stimulated lacrimal gland fluid secretion (13.26 +/- 1.47 microL/min) compared to the ovariectomized group (7.72 +/- 0.41 microL/min), but DHT treatment paradoxically decreased basal tear flow rate (1.02 +/- 0.04 microL/min) as compared to the ovariectomized rabbits (1.96 +/- 0.12 microL/min). DES decreased the total serum T from 59.33 +/- 10.54 pg/mL to 21.5 +/- 6.06 pg/mL. DES decreased total Na+,K(+)-ATPase by 12% and increased beta-adrenergic receptor binding sites by 83.3%. These results suggest that androgens play a major role in supporting lacrimal gland secretory function. Additionally, they suggest that estrogens may influence certain aspects of lacrimal functions, although it is not clear to what extent those actions are elicited directly or indirectly.