AGT and hypertensive disorder: Another study involving 106 hypertensive subjects also reported impaired gut epithelial barrier function characterized by elevated plasma levels of LPS and diamine oxidase, an enzyme primarily in the intestine for histamine catabolism.91 In several experimental models of HTN (ie, SHR,52 obstructive sleep apnea-induced HTN,86 chronic AngII-induced HTN52), impaired gut epithelial integrity and increased permeability were found.