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The control of cholesterol metabolism and plasma lipid levels in infant rats
1Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver, Canada.
Insights
Insulin, streptozotocin, and dexamethasone increase plasma triglycerides and cholesterol in infant rats. Enzyme activity in liver and adipose tissue inversely correlates with cholesterol, but not in the small intestine after insulin.
Area of Science:
- Endocrinology
- Metabolic Research
- Biochemistry
Background:
- Hormonal regulation of lipid metabolism is crucial for infant development.
- Understanding the effects of key hormones and toxins on lipid profiles is essential.
Purpose of the Study:
- To investigate the impact of insulin, anti-insulin serum, streptozotocin, antiglucagon serum, and dexamethasone on plasma lipid levels in infant rats.
- To examine the activity of 3-hydroxy-3-glutaryl CoA reductase in response to these treatments.
Main Methods:
- Infant rats were administered various substances via intraperitoneal injection.
- Plasma triglyceride and cholesterol levels were measured.
- Activity of 3-hydroxy-3-glutaryl CoA reductase in liver, brown adipose tissue, and small intestine was assessed.
Main Results:
- Insulin, streptozotocin, antiglucagon serum, and dexamethasone elevated plasma triglyceride levels.
- Anti-insulin serum and antiglucagon serum decreased plasma cholesterol, while streptozotocin, insulin, and dexamethasone increased it.
- Liver and brown adipose tissue 3-hydroxy-3-glutaryl CoA reductase activity showed an inverse relationship with plasma cholesterol levels.
- Small intestinal enzyme activity increased with insulin despite elevated plasma cholesterol.
Conclusions:
- Different hormonal and toxic agents exert distinct effects on lipid metabolism in infant rats.
- Insulin's effect on small intestinal lipid metabolism may differ from its systemic effects.
- Further research is needed to elucidate the mechanisms underlying these differential responses.
Abstract:
Infant rats received an i.p. injection of insulin, anti-insulin serum, streptozotocin, antiglucagon serum or dexamethasone. All substances except the antiinsulin serum, raised the plasma triglyceride level. Both antisera decreased plasma cholesterol levels, while streptozotocin, insulin and dexamethasone caused an increase. The activity of 3-hydroxy-3-glutaryl CoA reductase in liver and brown adipose tissue changed inversely to the cholesterol level. However, small intestinal enzyme activity was increased by insulin administration inspite of the rise in plasma cholesterol.