Evidence for anew role ofnatriuretic peptides: control ofintraocular pressure

To studythepossible physiological roleof atrial natriuretic peptide (ANP)intheregulationofintraocular pressure(IOP) theeffects ofan increase ofendogenous ANP within thephysiological range inducedby the neutral endopeptidase 24.11(NEP)inhibitor candoxatril wereexamined. Inasingle masked placebo controlled trial, sevenpatients were studied withnormal IOP(six male, onefemale; averageage50(range 37-62 years). Intraocular pressureineacheye was measured after 2 weeksofplacebo, after 4weeksofcandoxatril 200mg twice daily, andduring thefirst 3days of placebowashout. With4 weeksof candoxatril, endogenous plasma ANP levels increased from4-2(SEM1.5) to6*0(1.5) pmol/ I(p<004) andthere was asignificant decrease inmean arterial pressurefrom119(4)to110 (3) mm Hg(p<002; 12hoursafter treatment). There was asignificant reduction inIOPafter 4 weeks' treatment withcandoxatril (right eye 2.1(0.8) mm Hg,p<0'05paired ttest, left eye2*8(0.8) mm Hg,p<002). Themean fail in IOPwas 11%(4%)intheright eyeand16%(3%) intheleft eyeandthefall inIOPwas greater the higher theinitial IOP.Thereduction inIOP withchronic NEP inhibition was positively correlated withtheincrease inANP levels but notwithchanges inbloodpressure.These findings suggest thatANP may play aphysiological role intheregulation ofIOP.Asthefall inIOPwas greater insubjects withhigher initial IOP,NEP inhibitors may beoftherapeutic value inthemanagementofglaucoma. (BrJ3 Ophthalmol 1994; 78:446448)