title: Insulin Therapy of Nondiabetic Septic Patients Is Predicted by para-Tyrosine/Phenylalanine Ratio and by Hydroxyl Radical-Derived Products of Phenylalanine.
abstract: Hydroxyl radical converts Phe to para-, meta-, and ortho-Tyr (p-Tyr, m-Tyr, o-Tyr), while Phe is converted enzymatically to p-Tyr in the kidney and could serve as substrate for gluconeogenesis. Pathological isoforms m- and o-Tyr are supposed to be involved in development of hormone resistances. Role of Phe and the three Tyr isoforms in influencing insulin need was examined in 25 nondiabetic septic patients. Daily insulin dose (DID) and insulin-glucose product (IGP) were calculated. Serum and urinary levels of Phe and Tyr isoforms were determined using a rpHPLC-method. Urinary m-Tyr/p-Tyr ratio was higher in patients with DID and IGP over median compared to those below median (P = 0.005 and P = 0.01, resp.). Urinary m-Tyr and m-Tyr/p-Tyr ratio showed positive correlation with DID (P = 0.009 and P = 0.023, resp.) and with IGP (P = 0.004 and P = 0.008, resp.). Serum Phe was a negative predictor, while serum p-Tyr/Phe ratio was positive predictor of both DID and IGP. Urinary m-Tyr and urinary m-Tyr/p-Tyr, o-Tyr/p-Tyr, and (m-Tyr+o-Tyr)/p-Tyr ratios were positive predictors of both DID and IGP. Phe and Tyr isoforms have a predictive role in carbohydrate metabolism of nondiabetic septic patients. Phe may serve as substrate for renal gluconeogenesis via enzymatically produced p-Tyr, while hydroxyl radical derived Phe products may interfere with insulin action.
authors.affiliation: 2nd Department of Medicine and Nephrological Centre, Faculty of Medicine, University of Pécs, Pacsirta Street 1, Pécs 7624, Hungary.
authors.forename: Szilárd
authors.initials: S
authors.lastname: Kun
authors.affiliation: 2nd Department of Medicine and Nephrological Centre, Faculty of Medicine, University of Pécs, Pacsirta Street 1, Pécs 7624, Hungary.
authors.forename: Gergő A
authors.initials: GA
authors.lastname: Molnár
authors.affiliation: 2nd Department of Medicine and Nephrological Centre, Faculty of Medicine, University of Pécs, Pacsirta Street 1, Pécs 7624, Hungary.
authors.forename: Eszter
authors.initials: E
authors.lastname: Sélley
authors.affiliation: Department of Anaesthesia and Intensive Care, Faculty of Medicine, University of Pécs, Rákóczi Street 2, Pécs 7623, Hungary.
authors.forename: Lívia
authors.initials: L
authors.lastname: Szélig
authors.affiliation: Department of Anaesthesia and Intensive Care, Faculty of Medicine, University of Pécs, Rákóczi Street 2, Pécs 7623, Hungary.
authors.forename: Lajos
authors.initials: L
authors.lastname: Bogár
authors.affiliation: Department of Anaesthesia and Intensive Care, Faculty of Medicine, University of Pécs, Rákóczi Street 2, Pécs 7623, Hungary.
authors.forename: Csaba
authors.initials: C
authors.lastname: Csontos
authors.affiliation: Department of Laboratory Medicine, Faculty of Medicine, University of Pécs, Ifjúság Street 13, Pécs 7624, Hungary.
authors.forename: Attila
authors.initials: A
authors.lastname: Miseta
authors.affiliation: 2nd Department of Medicine and Nephrological Centre, Faculty of Medicine, University of Pécs, Pacsirta Street 1, Pécs 7624, Hungary.
authors.forename: István
authors.initials: I
authors.lastname: Wittmann
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D050260:Carbohydrate Metabolism / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005947:Glucose / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D017665:Hydroxyl Radical / Q000737:chemistry*; D007328:Insulin / Q000008:administration & dosage / Q000494:pharmacology; D007536:Isomerism; D008297:Male; D008875:Middle Aged; D010649:Phenylalanine / Q000097:blood / Q000737:chemistry* / Q000652:urine; D012772:Shock, Septic / Q000378:metabolism / Q000473:pathology; D014443:Tyrosine / Q000097:blood / Q000737:chemistry* / Q000652:urine
chemical_list: D007328:Insulin; D017665:Hydroxyl Radical; D014443:Tyrosine; D010649:Phenylalanine; D005947:Glucose