title: Catabolism and safety of supplemental L-arginine in animals.
abstract: L-arginine (Arg) is utilized via multiple pathways to synthesize protein and low-molecular-weight bioactive substances (e.g., nitric oxide, creatine, and polyamines) with enormous physiological importance. Furthermore, Arg regulates cell signaling pathways and gene expression to improve cardiovascular function, augment insulin sensitivity, enhance lean tissue mass, and reduce obesity in humans. Despite its versatile roles, the use of Arg as a dietary supplement is limited due to the lack of data to address concerns over its safety in humans. Data from animal studies are reviewed to assess arginine catabolism and the safety of long-term Arg supplementation. The arginase pathway was responsible for catabolism of 76-85 and 81-96 % Arg in extraintestinal tissues of pigs and rats, respectively. Dietary supplementation with Arg-HCl or the Arg base [315- and 630-mg Arg/(kg BW d) for 91 d] had no adverse effects on male or female pigs. Similarly, no safety issues were observed for male or female rats receiving supplementation with 1.8- and 3.6-g Arg/(kg BW d) for at least 91 d. Intravenous administration of Arg-HCl to gestating sheep at 81 and 180 mg Arg/(kg BW d) is safe for at least 82 and 40 d, respectively. Animals fed conventional diets can well tolerate large amounts of supplemental Arg [up to 630-mg Arg/(kg BW d) in pigs or 3.6-g Arg/(kg BW d) in rats] for 91 d, which are equivalent to 573-mg Arg/(kg BW d) for humans. Collectively, these results can help guide studies to determine the safety of long-term oral administration of Arg in humans.
authors.affiliation: State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, 100193, China.
authors.forename: Zhenlong
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Hubei Key Laboratory of Animal Nutrition and Feed Science, Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Wuhan Polytechnic University, Wuhan, 430023, China.
authors.forename: Yongqing
authors.initials: Y
authors.lastname: Hou
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, Texas, TX, 77843, USA.
authors.forename: Shengdi
authors.initials: S
authors.lastname: Hu
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, Texas, TX, 77843, USA.
authors.forename: Fuller W
authors.initials: FW
authors.lastname: Bazer
authors.affiliation: Department of Medical Physiology, Texas A&M Health Science Center, Temple, TX, 76504, USA.
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Meininger
authors.affiliation: Department of Internal Medicine, Baylor Scott and White Health, Temple, TX, 76508, USA.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: McNeal
authors.affiliation: State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, 100193, China. g-wu@tamu.edu.|Hubei Key Laboratory of Animal Nutrition and Feed Science, Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Wuhan Polytechnic University, Wuhan, 430023, China. g-wu@tamu.edu.|Department of Animal Science, Texas A&M University, College Station, Texas, TX, 77843, USA. g-wu@tamu.edu.|Department of Medical Physiology, Texas A&M Health Science Center, Temple, TX, 76504, USA. g-wu@tamu.edu.
authors.forename: Guoyao
authors.initials: G
authors.lastname: Wu
mesh_terms: D000818:Animals; D001119:Arginase / Q000378:metabolism*; D001120:Arginine / Q000009:adverse effects / Q000378:metabolism* / Q000494:pharmacology*; D019587:Dietary Supplements; D006801:Humans; D051381:Rats; D012756:Sheep; D013552:Swine
chemical_list: D001120:Arginine; D001119:Arginase
keywords: Amino acids; Catabolism; Dietary supplementation; Health; Nutrition