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Insulin receptors in isolated adipocytes from rats with different neonatal nutrition
Insights
Neonatal nutrition impacts insulin receptor properties in rat adipocytes. Smaller cells from underfed rats show higher insulin binding affinity, suggesting altered metabolic regulation.
Area of Science:
- Endocrinology
- Metabolic Research
- Cell Biology
Background:
- Neonatal nutrition is critical for long-term metabolic health.
- Adipocyte size and function are influenced by early-life nutrition.
- Insulin receptor properties regulate glucose uptake and metabolism.
Purpose of the Study:
- To investigate the long-term effects of altered neonatal nutrition on insulin receptor characteristics in rat adipocytes.
- To determine how variations in litter size during lactation impact adipocyte insulin binding.
- To correlate adipocyte size with insulin receptor density and binding affinity.
Main Methods:
- Rats were assigned to different litter sizes (4, 8, or 14 pups) to manipulate neonatal nutrition.
- Adipocytes were isolated from male rats at 30, 60, 120, and 500 days of age.
- Insulin binding studies were performed on isolated adipocytes to assess receptor properties.
Main Results:
- Total insulin receptor number per cell was consistent across adipocyte sizes.
- A negative correlation was observed between insulin binding sites per surface area and adipocyte size.
- Smaller adipocytes from underfed rats exhibited higher insulin binding affinity compared to larger adipocytes from overfed rats.
Conclusions:
- Neonatal nutrition significantly influences adipocyte insulin binding affinity, independent of total receptor number.
- Adipocyte size is inversely related to insulin receptor density and binding capacity.
- Early-life nutritional programming can lead to lasting alterations in insulin sensitivity at the cellular level.
Abstract:
The influence of different neonatal nutrition on the properties of insulin receptor in isolated adipocytes was studied. The changes of neonatal nutrition were achieved by adjustment of the number of sucklings to 4, 8 and 14 per one litter. After weaning (at the age of 30 days) the animals were fed standard pelleted diet ad libitum. The isolated fat cells from male rats neonatally overfed (i.e. 4 per litter), underfed (i.e. 14 per litter) and control group (i.e. 8 per litter) aged 30, 60, 120 and 500 days were prepared and used for insulin binding studies. The results showed that the total number of insulin receptors is the same in small and large adipocytes from neonatally over- or underfed animals, but a negative correlation between insulin binding sites per unit of surface area and fat cell size was found. The smaller adipocytes from neonatally underfed rats apparently showed a higher binding affinity to insulin as compared to larger fat cells from neonatally overfed animals.