Citrovorum Factor and Oviduct Response to Stilbestrol in Aminopterin-Treated Chicks

Summary

Data have been presented which show that Citrovorum Factor (CF) in a ratio to aminopterin of approximately 16:1, but not of 2:1, counteracts aminopterin inhibition of stilbestrol stimulation of the chick oviduct, while pteroylglutamic acid (PGA) in a ratio to aminopterin of 500:1 is 81% effective in this regard. That CF can substitute for PGA in permitting stilbestrol stimulation of the chick oviduct is further evidence consistent with the theory that CF is a metabolically active form of PGA.