title: Thirteen-week oral toxicity study of L-lysine hydrochloride in rats.
abstract: L-Lysine hydrochloride (Lys) is an essential amino acid in humans and animals, and it is used in animal feeds, in prevention of herpes simplex recurrence, and cereal fortification in some developing countries. This study evaluated toxicological and behavioral effects of Lys during a dosing study with male and female Sprague-Dawley rats. The amino acid was incorporated into a standard diet at doses equal to 1.25%, 2.5%, and 5.0% (w/w). A control group of rats received a standard diet. All diets were administered ad libitum for 13 consecutive weeks. To examine stability of any potential effects, the administration period was followed by a 5-week recovery period, during which only the standard diet was provided to all animals. In male and female rats in each concentration group, treatment-related changes were not observed in the clinical signs, body weights, diet consumption, water intake, ophthalmology, gross pathology, organ weights, or histology. A Lys-related drop in serum concentration and an increase in urine excretion of chlorides was a compensatory reaction to the ingested hydrochloride. No functional, biochemical, or histological changes in renal function were found. The no-observed-adverse-effect level (NOAEL) for Lys was estimated at 5.0% for both genders (male, 3.36 +/- 0.12 g/kg/day; female, 3.99 +/- 0.28 g/kg/day).
authors.affiliation: Health Services Development Department, Ajinomoto Co. Inc., 1-15-1 Chuo-ku, 104-8315 Tokyo, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Tsubuku
authors.forename: Masahiro
authors.initials: M
authors.lastname: Mochizuki
authors.forename: Kazunori
authors.initials: K
authors.lastname: Mawatari
authors.forename: Miro
authors.initials: M
authors.lastname: Smriga
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kimura
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001774:Blood Chemical Analysis; D001835:Body Weight / Q000187:drug effects; D019587:Dietary Supplements / Q000633:toxicity; D005260:Female; D006403:Hematologic Tests; D008239:Lysine / Q000633:toxicity*; D008297:Male; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012737:Sex Factors; D036401:Toxicity Tests, Chronic; D016482:Urinalysis
chemical_list: D008239:Lysine