Carnitine Transferases in Brown Fat of Newborn and Developing Primates

Abstract

Carnitine acetyl (CAT) and carnitine palmitoyltransferase (CPT) activities were determined in skeletal muscle, heart, liver and brown fat of fetal and adult monkeys. CAT activity was highest in brown adipose tissue at all ages, but there was no significant change with age. Muscle CAT activity was lowest and also not related to age. In both heart and liver, however, there was a significant (p < 0.01) increase with age. CPT activity, on the other hand, did not differ from organ to organ or with age. In brown fat from newborn dead human babies CAT activity was between 100 and 270 nmol/mg protein/min, much higher than in a spontaneously aborted 1,500-gram fetus (25 nmol). The highest CAT activity in newborns was found in muscle.

Carnitine Acetyltransferase in Developing Mammals

“…It would seem, however, that rat liver is exceptional insofar as its CAT activity is very low compared to other rat tissues and also compared to liver tissue of rabbit and guinea pigs, but also monkeys and man (8).…”

Carnitine Acetyltransferase in Developing Mammals

“…It would seem, however, that rat liver is exceptional insofar as its CAT activity is very low compared to other rat tissues and also compared to liver tissue of rabbit and guinea pigs, but also monkeys and man (8).…”

Human Growth

“…Ketone-body production from longchain fatty acids is also low ~fore birth because of low activity of all enzymes needed for the conversion of these precursors into acetoacetate. In the primate (man and monkeys), however, fetal liver maintains a high rate of fatty acid oxidation throughout gestation (Roux et aI., 1970), probably the result of high carnitine transferase activity in primate fetal liver (Hahn et al, 1976). There is evidence also that endogenous fatty acids are oxidized at higher rates than the exogenous fatty acids studied (Lockwood and Bailey, 1970).…”

Carnitine Acetyltransferase in Developing Mammals

“…It would seem, however, that rat liver is exceptional insofar as its CAT activity is very low compared to other rat tissues and also compared to liver tissue of rabbit and guinea pigs, but also monkeys and man (8).…”

Human Growth

“…Ketone-body production from longchain fatty acids is also low ~fore birth because of low activity of all enzymes needed for the conversion of these precursors into acetoacetate. In the primate (man and monkeys), however, fetal liver maintains a high rate of fatty acid oxidation throughout gestation (Roux et aI., 1970), probably the result of high carnitine transferase activity in primate fetal liver (Hahn et al, 1976). There is evidence also that endogenous fatty acids are oxidized at higher rates than the exogenous fatty acids studied (Lockwood and Bailey, 1970).…”

Carnitine Acetyltransferase in Developing Mammals

“…It would seem, however, that rat liver is exceptional insofar as its CAT activity is very low compared to other rat tissues and also compared to liver tissue of rabbit and guinea pigs, but also monkeys and man (8).…”

Human Growth

“…Ketone-body production from longchain fatty acids is also low ~fore birth because of low activity of all enzymes needed for the conversion of these precursors into acetoacetate. In the primate (man and monkeys), however, fetal liver maintains a high rate of fatty acid oxidation throughout gestation (Roux et aI., 1970), probably the result of high carnitine transferase activity in primate fetal liver (Hahn et al, 1976). There is evidence also that endogenous fatty acids are oxidized at higher rates than the exogenous fatty acids studied (Lockwood and Bailey, 1970).…”