Sep 1, 1973

Two distinct types of enhancement of galactose uptake into hamster cells: tumor-virus transformation and hexose starvation

Proceedings of the National Academy of Sciences of the United States of America
H M Kalckar, D B Ullrey

Abstract

Enhancement of hexose uptake seems well correlated with transformation of cell cultures by tumor viruses and the absence of contact inhibition. Enhancement of sugar uptake has also been observed as a result of hexose starvation. Both types of enhancement can clearly be demonstrated in cultures of hamster cells when uptake of (14)C-labeled galactose is monitored after 10 or 20 min. The profiles of accumulation products are strikingly different. In cultures of hamster NIL cells transformed with polyoma virus much of the (14)C is accumulated as UDPhexose. Untransformed cells accumulate galactose-l-phosphate as well as UDPhexose. Hexose-starved cells show enhanced uptake of galactose; however, this marked enhancement was only observed in NIL cultures close to contact inhibition. The novel and common feature seen in hexose-starved cells when incubated briefly with (14)C-labeled galactose is the occurrence of a marked accumulation of [(14)C]UDPglucuronic acid at the expense of UDPhexose. The ratio [(14)C]UDPglucuronic acid/UDPhexose in cultures fed glucose or galactose was invariably low (0.15-0.2) regardless of the presence or absence of contact inhibition. 20 hr of hexose starvation invariably changed this ratio by a factor of 10 o...Continue Reading

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  • Citations35

References

Mentioned in this Paper

Galactose Measurement
Oncogenic Viruses
Hexoses
Uptake
Cell Culture Techniques
Hamsters
Phosphate Measurement
Glucose, (beta-D)-Isomer
Galactose
Uridine Diphosphate Sugars

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