Yokohira Masanao, Hosokawa Kyoko, Yamakawa Keiko, Hashimoto Nozomi, Suzuki Satoshi, Matsuda Yoko, Saoo Kousuke, Kuno Toshiya, Imaida Katsumi
Onco-Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan.
Food Chem Toxicol. 2008 Jul;46(7):2568-72. doi: 10.1016/j.fct.2008.04.014. Epub 2008 Apr 22.
L-asparagine is an amino acid listed as an existing food additive in Japan. The present 90-day toxicity study in F344/DuCrlCrj rats was conducted for safety assessment and to determine a no observed adverse effect level (NOAEL) of L-asparagine. Groups of 10 males and 10 females were given the material at dose levels of 0%, 1.25%, 2.5% or 5% in diet for 90 days. During the experiment, there were no remarkable changes in general conditions and no deaths occurred in any group. Final body weights of male 5% and 1.25% groups were significantly decreased. There were also significant increases in relative organ weights of the brain, kidney and testis in 5% males. On serological examination, GLU, PL, K and ALT were increased significantly in 5% females, and GLU was increased significantly and CRN was decreased significantly in the female 1.25% group. However, histopathological examination did not reveal any significant variation in development of lesions among the groups. Changes in body and organ weights, as well as other parameters, were concluded to be due to treatment with 5% L-asparagine. The NOAEL was determined to be 2.5% in the diet (males, 1.65 g/kg body weight/day; females, 1.73 g/kg body weight/day).
