Possible Interaction: Aminopterin and Folic Acid

“Protection against aminopterin interference with stilbestrol stimulation of the chick oviduct is afforded by PGA given one hour prior to aminopterin (Hertz, 1948; Hertz and Tullner, 1949; Kline and Dorfman, 1951b).”

“The binding of folic acid to the human binder was inhibited by folate > H4-folate > methyl-H4-folate ≃dihydrofolate ≃ pteroic acid ≫ methotrexate ≃ aminopterin.”

“ Aminopterin competes with folic acid to prevent its conversion to folinic acid and also competes with folinic acid in its biochemical reactions.”

“These two values are remarkably close, indicating a constant relative inhibitive effect of aminopterin to the concentration of PGA.”

“ Folic acid exhibited a 3-fold higher Km than aminopterin.”

“Uptake and conversion of [3H]folic acid to polyglutamate derivatives by rat liver and kidney were inhibited by methotrexate or aminopterin (15 mg/kg body weight) and DL-tetrahydromethotrexate (30 mg/kg body weight).”

“When added to duck adrenal mitochondrial or microsomal preparations aminopterin effected a concentration dependent inhibition of the 11β- or 21-hydroxylase activity while the presence of folic acid resulted in a concentration dependent stimulation.”

“High concentrations of folic acid in the medium were able to inhibit the transport of aminopterin.”

“When folic acid treatment was followed by that of aminopterin the mitotic index was very high and all the mitotic stages occurred; this suggests that in Acantholyda nemoralis folate offers some protection against the inhibition of mitoses by its analogue.”

“Injection of either Methotrexate or Aminopterin into the yolk on the eighth day of incubation inhibits the in vitro conversion of PGA by yolk sac homogenates 2 and 4 days later and the conversion by embryonic liver homogenates 10 days later.”