Cystathionine excretion in relation to vitamin B-6 nutriture of rats: strain differences and effects of DL- or L-methionine supplementation.
Wistar and Long-Evans rats excreted significantly more cystathionine during days 27 to 31 of a vitamin B-6 deficiency than did Spague-Dawley rats. Wistar rats were therefore chosen for experiments designed to test the effects of dietary DL- and L-methionine supplementation upon cystathionine excretion of vitamin B-6-deficient and control rats. Methionine supplementation did not significantly affect mean daily food consumption or weight gain of the control animals. L-Methionine-supplemented, deficient rats gained significantly more during the first 15 days of the experiment and less during the last 11 days than did the other deficient groups. No cystathionine was detected in the urine of methionine-supplemented or unsupplemented control rats between days 8 and 26 of the experiment; but measurable quantities of cystathionine were present in the urine of all deficient groups by days 8 to 12. Deficient animals fed DL-methionine excreted up to 2.33 mg more cystahionine per 4-day period than did the unsupplemented deficient rats, whereas rats fed L-methionine excreted up to 7.44 mg more per 4-day period than did the unsupplemented ones. This difference in cystathionine response was highly significant and indicates that the L supplement stressed the vitamin B-6-deficient rats more than did the DL supplement. An explanation for this may be that the D isomer in the DL supplement was not as efficiently absorbed and/or metabolized as the L form.
D000818:Animals; D003540:Cystathionine / Q000652:urine*; D004032:Diet; D008297:Male; D008715:Methionine / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D013045:Species Specificity; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D026681:Vitamin B 6 Deficiency / Q000378:metabolism*
D003540:Cystathionine; D008715:Methionine