Endothelin-like immunoreactivity in aqueous humor of patients with primary open-angle glaucoma and cataract

Background: Experimental evidence suggests a role of endothelin-l (ET) in the regulation of intraocular pressure (IOP). Method: Therefore, in patients undergoing cataract surgery, ET-like immunoreactivity (ETIR) was measured by radioimmunoassay in pooled samples of aqueous humor of eyes with primary open-angle glaucoma (POAG) and normotensive eyes with cataract only. Results: ETIR was significantly (P < 0.05) higher in patients with cataract and POAG (20.5 +/- 1.8 pg/ml, n = 12; preoperative IOP 21.4 +/- 1.1 mmHg, n = 33) than in patients with cataract only (15.8 +/- 1.6 pg/ml, n = 15; preoperative IOP 16.0 +/- 0.6 mmHg, n = 77). Conclusion: This finding may indicate a role of ET in POAG or ocular antihypertensive treatment, and its relevance should be further investigated.