SAMe concentrations increased significantly, with peak concentrations achieved 2 to 4 hours after dosing in 78% of the cats. Peak or cumulative plasma concentrations of SAMe did not change with long-term dosing, suggesting a lack of substantial change in enteric degradation, uptake, enterohepatic cycling, systemic metabolism, or elimination with long-term administration. The authors also noted a positive influence of SAMe on RBCs and hepatic redox status (oxidative membrane products in RBCs were reduced 21.1%, liver glutathione was increased 35%, and liver reduced glutathione-oxidized disulfide glutathione ratio was increased 69%), improved RBC resilience against osmotic challenge, bile acid-independent choleresis, and improved histologic characteristics in cats with asymptomatic nonsuppurative portal inflammation. The authors thus concluded that the form of SAMe used in the study is enterically available and suggest that it imparts biologic effects that may be useful for attenuating systemic or hepatic oxidant challenge.
COMMENTARY: The significance and potential control of oxidative injury in all species is a rapidly growing area of interest in veterinary medicine. There is growing evidence that such injury may lead to a variety of degenerative conditions such as arthritis, aging, and cancer, and that administration of antioxidants may alter the course of these processes. This particular study examined the use of SAMe in healthy cats with results that are encouraging-oral SAMe was bioavailable and produced detectable biologic responses in clinically normal cats. These baseline studies are vital to our understanding of the therapeutic application of this compound in health and disease.
The effects of S-adenosylmethionine on clinical pathology and redox potential in the red blood cell, liver, and bile of clinically normal cats. Center SA, Randolph JF, Warner KL, et al. J VET INTERN MED 19:303-314, 2005.
