snímek PPT
Decreased intake: alcoholism, hepatic diseases,
tropical sprue (?coliform bacteria), malabsorption,
resections. Increased requirements: gravidity, growth,
?hematopoiesis. Folic acid antagonists: cytostatics,
chemotherapeutics, antiparasitic and anticonvulsive
drugs
Function of tetrahydrofolate: coenzyme for single-
carbon transfers ? necessary for thymidylate
synthase ? rate limiting for DNA synthesis
Vitamin Bl2 deficiency (Megaloblastic anemia)
Synthetized by microbes only ? in foods of animal
origin. Requirements small, stores large.
Absorption of B12 Fig. 18