Histochemical pattern of tetrahydrofolate dehydrogenase in hemopoietic cells following folate antagonist treatment in vivo
Nano, R.; Gerzeli, G.; Gervaso, M.V.; De Piceis Polver, P.; Arisi, C.
Cellular and Molecular Biology Including Cyto-Enzymology 24(3): 191-197
1979
ISSN/ISBN: 0145-5680 PMID: 498204 Document Number: 144734
Folate antagonists may interfere to a varying extent with the histochemical demonstration of tetrahydrofolate dehydrogenase, when added to the incubation medium and also after in vivo pretreatment. To elucidate some aspects of this interaction, adult male rats were injected s.c. for 3 consecutive days with aminopterin (0.025 mg/100 g of body wt per day) or amethopterin (0.15 mg/100 g body wt per day). The rats were sacrificed at different times, up to 34 days after the end of treatment. Tetrahydrofolate dehydrogenase reaction was performed according to the method proposed by Gerzeli and De Piceis Polver. The possibility of tetrahydrofolate dehydrogenase inhibition following in vivo folate antagonist treatment was demonstrated. This fact appeared especially evident in erythroblasts and in the most immature elements of the granulocytic series, following aminopterin at least up to the 9th day. At later times (2 wk or more after the end of treatment) the histochemically-detectable activity of tetrahydrofolate dehydrogenase not only goes back to control levels but may even exceed them. Changes in reaction intensity may be connected with protection of the antagonist-bound enzyme from its normal metabolic degradation.