Analyses of aqueous humour ghrelin levels of eyes with and without glaucoma
- 1Laboratory of Physiology, Faculty of Medicine, University of Porto, Portugal
- 2Ophthalmology Division, Faculty of Medicine, University of Porto, Portugal
- Dr A A Rocha-Sousa, Department of Physiology, Faculty of Medicine, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal; arsousa{at}med.up.pt
- Accepted 31 July 2008
Ghrelin is an acylated, 28-amino-acid peptide isolated from human and rat gastric oxyntic mucosa,1 with actions mediated by the GHSR-1a receptor. The ability of ghrelin to activate GHSR-1a is dependent on the presence of an octanoyl-(acyl)-chain in serine-3.2 As almost 90% of circulating ghrelin lacks this chain3 and this desacylated form (des-acyl-ghrelin) has biological effects, this means that these effects are not mediated by GHSR-1a. The presence of ghrelin in the rat posterior epithelium of the iris and non-pigmented ciliary epithelium was recently demonstrated.4 It relaxes both the iris sphincter and dilator muscles, through a GHSR-1a-dependent mechanism in the dilator, but GHSR-1a-independent in the sphincter.4 In ocular tissues, obestatin, a peptide derived from the ghrelin gene,5 promotes the proliferation of human retinal pigmentary epithelium cells6 and potentiates cholinergic contraction.7
The aim of our study was to determine the AqH levels of ghrelin and des-acyl-ghrelin in patients with and without glaucoma that underwent cataract surgery.
Methods
This prospective study included consecutive patients with (n = 9) and without (n = 15) open-angle glaucoma who were …









