The ability of the rat to metabolize myristoyl-methionine: an acylamino acid with potentially useful antibacterial properties.
Two experiments with Sprague Dawley rats tested their ability to hydrolyse myristoyl-methionine (M-M) into myristic acid and L-methionine (M). In the first experiment, lasting for 3 days. male rats were orally administered [9,10-3H]myristoyl-L-[35S]methionine. The recovery of radioactivity was approximately 90% for both isotopes; 19% of the administered 3H was recovered in the urine and 16% in the faeces, while the recovered 35S activity was 13 and 12%, respectively. The balance of the radioactivity was found among the tissues, organs and blood. In the second experiment, male and female rats received soybean-based diets which were supplemented with either 0.305% M-M or 0.2% M (both diets contained equal amounts of M) for periods up to 4 weeks. The growth rate of the rats receiving the 0.305% M-M diets was slightly slower than that for the rats on the 0.2% M diet, but the difference was not statistically significant (P > 0.05). The M-M rats had a transitory decrease in feed consumption, suggesting that palatability may have contributed to the growth difference and that a somewhat greater amount of M-M was necessary for the rat to attain the same growth rate as that produced by 0.2% M. When the amount of dietary M-M was increased to 3.05% M-M, a greater reduction in feed consumption and body weight gain was observed. This latter diet was an initial attempt to study the potential toxicity of M-M. None of the haematological, clinical chemistry or organ weight data suggested that M-M was overtly toxic per se, but longer-term feeding studies are needed to evaluate the potential toxicity of M-M more fully.
Arnold
D L
DL
Toxicology Research Division, Bureau of Chemical Safety, Health Canada, Ottawa, Ontario.
McGuire
P F
PF
Miller
D
D
Malcolm
S
S
Hayward
S
S
Paquet
A
A
D000284:Administration, Oral; D000821:Animal Feed; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000378:metabolism* / Q000493:pharmacokinetics / Q000633:toxicity; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001835:Body Weight / Q000187:drug effects; D004032:Diet; D019587:Dietary Supplements; D004435:Eating / Q000187:drug effects; D005243:Feces / Q000737:chemistry; D005260:Female; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics / Q000633:toxicity; D009227:Myristic Acids / Q000378:metabolism* / Q000493:pharmacokinetics / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D012737:Sex Factors; D013462:Sulfur Radioisotopes; D014018:Tissue Distribution; D014316:Tritium
D000894:Anti-Inflammatory Agents, Non-Steroidal; D015415:Biomarkers; D009227:Myristic Acids; D013462:Sulfur Radioisotopes; C114536:myristoylmethionine; D014316:Tritium; D008715:Methionine