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Fructose-1,6-biphosphatase activity in the intestinal mucosa of developing rats
Insights
Fructose-biphosphatase activity in rat intestines peaks around day 10 and decreases thereafter. Hormones and diet influence this key enzyme
Area of Science:
- Biochemistry
- Developmental Biology
- Gastroenterology
Background:
- Fructose-biphosphatase (EC 3.1.3.11) is a crucial enzyme in gluconeogenesis.
- Its activity in the small intestine is vital for energy metabolism during development.
- Understanding its regulation is key to comprehending intestinal maturation.
Purpose of the Study:
- To investigate the developmental changes in fructose-biphosphatase activity in rat small intestine.
- To examine the influence of hormones (cortisone, triiodothyronine) and diet on enzyme activity.
- To compare activity in proximal versus distal intestinal segments.
Main Methods:
- Measurement of fructose-biphosphatase activity in rat intestinal mucosa from 1 to 30 days postnatal.
- Assay of enzyme activity following administration of cortisone or triiodothyronine.
- Analysis of enzyme activity in rats weaned onto a high-fat diet.
Main Results:
- Fructose-biphosphatase activity increased to a maximum around postnatal day 10, then declined.
- Activity was consistently higher in the proximal than the distal small intestine.
- Cortisone and triiodothyronine decreased activity in 10-day-old rats; cortisone's effect diminished by day 14. High-fat diet delayed but did not prevent the post-weaning decrease.
Conclusions:
- Rat small intestinal fructose-biphosphatase activity exhibits a distinct developmental profile.
- Hormonal and dietary factors modulate this enzyme's activity during postnatal development.
- These findings highlight the dynamic regulation of carbohydrate metabolism in the developing gut.
Abstract:
Fructose-biphosphatase (EC 3.1.3.11) activity was determined in the proximal and distal parts of the small intestinal mucosa of rats 1-30 days of age. Activity was found to increase to a maximum on about the 10th postnatal day and then to decrease. It was always higher in the proximal than in the distal portion of the gut. The enzyme showed a wide range of pH optimum around 7.0 and was inhibited by AMP. In 10-day-old rats activity determined 24 or 48 h after a single injection of cortisone or triiodothyronine was significantly decreased. This effect was no longer found for cortisone in 14-day-old animals. Weaning 18-day-old rats to a high-fat diet for 5 or 7 days delayed but did not prevent the usual decrease in activity seen at weaning.