5 beta-Dihydrocortisol: possible mediator of the ocular hypertension in glaucoma.

5 beta-dihydrocortisol potentiates the action of topically applied dexamethasone in raising the intraocular pressure (IOP) in young rabbits. Dexamethasone (0.06%) plus 5 beta-dihydrocortisol (0.1 and 1.0%) elevated the IOP 7-10 mmHg within 18 days of treatment. By contrast, 0.06% dexamethasone alone raised the IOP 3 to 4 mmHg in a similar period of time. Since 5 beta-dihydrocortisol accumulates abnormally in cultured cells derived from the outflow region of the eye from patients with primary open angle glaucoma (POAG), a similar potentiation in man may account for the sensitivity of these patients to the IOP raising effect of glucocorticoids. Further, this metabolite may potentiate endogenous glucocorticoids resulting in the ocular hypertension characteristic of POAG.