JBC, Vol. 251, Issue 7, 2147-2154, Apr, 1976
Biochemical and ultrastructural hepatic changes during vitamin B12 deficiency in animals and man
E. P. Frenkel, A. Mukherjee, C. R. Hackenbrock and P. A. Srere
Vitamin B12 deficiency has been shown to result in an increase in content
and activity of the hepatic cytosolic enzymes of fatty acid synthesis. The
present study demonstrated that ATP citrate lyase, an enzyme whose activity
has been positively correlated with rates of fatty acid biosynthesis, also
increased in the livers of B12-deficient animals. Total and specific
activity of hepatic citrate synthase, an enzyme whose activity is
unaffected by a variety of dietary and hormonal changes, also was found to
be increased in the B12-deprived state. By contrast, the activity of
hepatic succinate-cytochrome c reductase, a portion of a multicomponent
enzyme complex synthesized in part within the mitochondria, was unchanged
in B12 deficiency. Vitamin B12 deprivation resulted in an increase in
hepatic mitochondrial cristae membranes in both animals and man.
Histochemical and chemical analysis demonstrated increased glycogen in the
liver cells from B12-deficient animals and man. Thus, in the livers from
vitamin B12-deficient animals there is an increased activity of the
otherwise highly constant Krebs cycle enzyme citrate synthase, and in both
animals and man there are increased mitochondrial cristae membranes.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?