-transparent.png){kind=logo}
The effects of leucine and alpha-ketoisocaproic acid on the NAD biosynthesis from (carboxyl-14C) nicotinic acid or (benzene ring-U-14C) tryptophan were investigated in the isolated rat liver cells. The quantities of NAD formed from tryptophan and nicotinic acid increased linearly during 60 min-incubation. Leucine, which was essentially not metabolized by the isolated liver cells, had no inhibitory effect on the NAD synthesis. On the other hand, alpha-ketoisocaproic acid, alpha-keto acid analogue of leucine, which was rapidly metabolized to ketone bodies, diminished a quantity and a specific radioactivity of NAD synthesized from both tryptophan and nicotinic acid to a similar extent. Palmitic acid, which was oxidized to ketone bodies by the isolated rat liver cells, also diminished an amount and a specific radioactivity of NAD synthesized from nicotinic acid. Ketone bodies exogenously added to the incubation medium exerted a similar inhibitory effect on NAD synthesis. Results demonstrate that substances which can be oxidized to ketone bodies are inhibitory to NAD biosynthesis from tryptophan and nicotinic acid in the isolated rat liver cells.
O Yamada, and
M Shin, and
K Sano, and
C Umezawa
January 1998,
International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition,
O Yamada, and
M Shin, and
K Sano, and
C Umezawa
January 1972,
Verhandlungen der Deutschen Gesellschaft fur Innere Medizin,
O Yamada, and
M Shin, and
K Sano, and
C Umezawa
January 1971,
Ukrains'kyi biokhimichnyi zhurnal,
O Yamada, and
M Shin, and
K Sano, and
C Umezawa
December 2002,
Drug metabolism and disposition: the biological fate of chemicals,
O Yamada, and
M Shin, and
K Sano, and
C Umezawa
July 1976,
Biochimica et biophysica acta,
O Yamada, and
M Shin, and
K Sano, and
C Umezawa
April 2010,
Brain research,
O Yamada, and
M Shin, and
K Sano, and
C Umezawa
March 1970,
The Journal of clinical endocrinology and metabolism,
O Yamada, and
M Shin, and
K Sano, and
C Umezawa
April 1974,
Diabetologia,
O Yamada, and
M Shin, and
K Sano, and
C Umezawa
April 1972,
Zeitschrift fur klinische Chemie und klinische Biochemie,
O Yamada, and
M Shin, and
K Sano, and
C Umezawa
April 1961,
Biologia neonatorum. Neo-natal studies,
