Nutritional regulation of hepatic glucose-6-phosphate dehydrogenase. Transient activation of transcription.

Hepatic glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) is subject to nutritional and hormonal regulation. Previous work has shown that increased amounts of mRNA encoding G6PDH can account for the increase in enzyme activity. The results of this study demonstrate that transcription of the G6PDH gene is transiently elevated after ingestion of a high-carbohydrate diet. However, the increased rate of transcription cannot totally account for the increased G6PDH mRNA. The half-life of the G6PDH mRNA appears to be about 4-5-fold higher during ingestion of a high-carbohydrate diet. Thus increased transcription as well as mRNA stability are each partially responsible for the nutritional regulation of G6PDH mRNA.