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Erythrocyte insulin binding in normal infants, children and adults
Insights
Insulin binding to red blood cells (erythrocytes) varies significantly with age, being highest in newborns and decreasing throughout infancy. These findings highlight the need for age-specific controls in diabetes research.
Area of Science:
- Endocrinology
- Physiology
- Cell Biology
Background:
- Insulin resistance is a key factor in metabolic disorders.
- Understanding normal insulin-receptor interactions is crucial for disease diagnosis.
- Erythrocyte insulin binding serves as a model for studying insulin sensitivity.
Purpose of the Study:
- To establish normal insulin binding criteria in erythrocytes across different age groups.
- To investigate age-related changes in insulin binding characteristics.
- To determine the influence of age on insulin receptor concentration and affinity.
Main Methods:
- Studied insulin binding to erythrocytes from normal subjects of varying ages.
- Measured insulin binding at tracer and physiological concentrations.
- Analyzed receptor concentration and affinity in different age cohorts.
Main Results:
- Insulin binding was significantly higher in cord blood and infant erythrocytes compared to children and adults.
- Maximum insulin binding in infants (1-12 months) was higher than in children and negatively correlated with age.
- Erythrocytes from men showed higher insulin binding than women, linked to receptor affinity.
- No correlation was found between insulin binding and circulating insulin or C-peptide levels.
Conclusions:
- Age-specific reference ranges for erythrocyte insulin binding are essential.
- Significant age-dependent variations in insulin binding occur, particularly in the first year of life.
- These findings underscore the importance of using age-matched controls in studies of erythrocyte insulin binding in disease states.
Abstract:
To establish normal insulin binding criteria, we studied the binding of insulin to erythrocytes from normal subjects of different ages. Insulin binding to cord erythrocytes and to erythrocytes from infants aged 2-7 days was significantly higher at tracer and physiological insulin concentrations than was binding to cells from children aged 1-15 years and adults. In infants aged 1-12 months the maximum insulin binding to erythrocytes was significantly higher than that to erythrocytes from children, and in addition, it correlated negatively with age. An increase in receptor concentration was found in cord erythrocytes whereas an increased receptor affinity for insulin was found in erythrocytes from infants. Insulin binding characteristics in erythrocytes from prepubertal and pubertal children were basically similar to those in women. Erythrocytes from men bound significantly higher amounts of insulin than did those from women. This difference was associated with changes in receptor affinity for insulin. There was no correlation between the insulin binding characteristics and the circulating concentration of insulin or C-peptide. The increased erythrocyte insulin binding at birth persisted over the neonatal period. There was an overall negative correlation between the maximum insulin binding and age in the subjects studied, but the major decrease in erythrocytes insulin binding occurred during the first year of life past the neonatal period. These observations stress the importance of using age-matched controls in studies on erythrocyte insulin binding in disease states.