A simple HPLC method for the determination of S-adenosylmethionine and S-adenosylhomocysteine in rat tissues: the effect of vitamin B6 deficiency on these concentrations in rat liver.

A simple method using isocratic HPLC with ultraviolet detection was established for the simultaneous measurement of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) in rat tissues. The method provides rapid resolution of both compounds in a single run by direct injection of the perchloric acid extract of tissue, so that sampling procedures and analytical errors can be reduced in determining the SAM/SAH ratio, a measure of transmethylation reactions. The assay has a detection limit of 25 pmol and is linear in the range 50-200 pmol. This procedure was applied to determine the change of SAM/SAH ratio in liver caused by vitamin B6 deficiency. The marked reduction of the SAM/SAH ratios in vitamin B6-deficient rats were due to a drastic rise in SAH concentration with a concurrent striking decrease in SAM concentration.