title: Amino Acid Availability Regulates the Effect of Hyperinsulinemia on Skin Protein Metabolism in Pigs.
abstract: The effects of amino acid supply and insulin infusion on skin protein kinetics (fractional synthesis rate (FSR), fractional breakdown rate (FBR), and net balance (NB)) in pigs were investigated. Four-month-old pigs were divided into four groups as follows: control, insulin (INS), amino acid (AA), and INS + AA groups based on the nutritional and hormonal conditions. l-[ring-(13)C6]Phenylalanine was infused. FBR was estimated from the enrichment ratio of arterial phenylalanine to intracellular free phenylalanine. Plasma INS was increased (p < 0.05) in the INS and INS + AA groups. Plasma glucose was maintained by infusion of glucose in the groups receiving INS. The interventions did not change the NB of skin protein. However, the interventions affected the FSR and FBR differently. An infusion of INS significantly increased both FSR and FBR, although AA infusion did not. When an AA infusion was added to the infusion of insulin (INS + AA group), FSR and FBR were both lower when compared with the INS group. Our data demonstrate that in anesthetized pigs INS infusion did not exert an anabolic effect, but rather it increased AA cycling into and out of skin protein. Because co-infusion of AAs with INS ameliorated this effect, it is likely that the increased AA cycling during INS infusion was related to AA supply. Although protein kinetics were affected by both INS and AAs, none of the interventions affected the skin protein deposition. Thus, skin protein content is closely regulated under normal circumstances and is not subject to transient changes in AAs or hormonal concentrations.
authors.affiliation: Departments of Internal Medicine, Shriners Hospitals for Children, Galveston, Texas 77555. Electronic address: detuvden@utmb.edu.
authors.forename: Demidmaa
authors.initials: D
authors.lastname: Tuvdendorj
authors.affiliation: Departments of Pediatrics, Center for Translational Research in Aging and Longevity, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205; Departments of Geriatrics, Center for Translational Research in Aging and Longevity, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205; Arkansas Children's Nutrition Center, Little Rock, Arkansas 72205; Arkansas Children's Hospital Research Institute, Little Rock, Arkansas 72205.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Børsheim
authors.affiliation: Departments of Surgery, University of Texas Medical Branch, Shriners Hospitals for Children, Galveston, Texas 77555; Departments of Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas 77555.
authors.forename: Carwyn P
authors.initials: CP
authors.lastname: Sharp
authors.affiliation: Departments of Surgery, University of Texas Medical Branch, Shriners Hospitals for Children, Galveston, Texas 77555; Departments of Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas 77555.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Departments of Surgery, University of Texas Medical Branch, Shriners Hospitals for Children, Galveston, Texas 77555; Departments of Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas 77555.
authors.forename: Carrie M
authors.initials: CM
authors.lastname: Barone
authors.affiliation: Departments of Surgery, University of Texas Medical Branch, Shriners Hospitals for Children, Galveston, Texas 77555; Departments of Metabolism Unit, Shriners Hospitals for Children, Galveston, Texas 77555.
authors.forename: David L
authors.initials: DL
authors.lastname: Chinkes
authors.affiliation: Departments of Geriatrics, Center for Translational Research in Aging and Longevity, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Wolfe
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D005260:Female; D006946:Hyperinsulinism / Q000378:metabolism* / Q000503:physiopathology / Q000662:veterinary*; D012867:Skin / Q000378:metabolism* / Q000503:physiopathology; D013552:Swine / Q000378:metabolism*
chemical_list: D000596:Amino Acids
keywords: amino acid; hyperaminoacidemia; hyperinsulinemia; insulin; isotopic tracer; protein breakdown; protein synthesis; skin