Metabolism of Hydroxylysine by Rats

Abstract

SL- and DL-allo-5-hydroxylysine-6-¹⁴C and L-5-hydroxlysine-³H were administered intraperitoneally to intact rats and the degradative products were trapped by the metabolite overloading technique. Hydroxylysine was readily oxidized; approximately 40% of the ¹⁴C was expired as ¹⁴CO₂ in 24 hours. Urinary 5- hydroxypipecolate, α-ketoadipate, glutarate and crotonate were identified as labeled degradation products isolated from the urine. The specific activities of glutamate, aspartate and alanine isolated from the carcass protein were too low to permit the determination of the labeling pattern. This low activity and the rapid release of ¹⁴CO₂ suggests that C₍₆₎ of hydroxylysine reaches these amino acids via ¹⁴CO₂. The degradation of hydroxylysine appears to proceed by reactions parallel to those which degrade lysine with the site of dehydroxylation as yet uncertain.