The insulin receptor in normal and obese persons

Area of Science:

• Endocrinology
• Metabolic Research
• Cell Biology

Background:

• Obesity is often associated with insulin resistance and hyperinsulinism.
• Understanding the role of insulin receptors in obesity is crucial for metabolic health.

Purpose of the Study:

• To investigate insulin receptor binding in obese versus normal-weight individuals.
• To explore correlations between insulin receptors, body weight, fat cell size, and fasting insulin levels.
• To assess the impact of fasting on insulin receptor numbers and plasma insulin in obese subjects.

Main Methods:

• Studied insulin binding to mononuclear leucocytes using [125I]insulin.
• Compared insulin binding fractions between 21 healthy and 22 obese subjects.
• Analyzed correlations between insulin receptors, body weight, fat cell size, and fasting plasma insulin.
• Monitored insulin receptors and plasma insulin in 11 obese subjects before and after a 10-day fast.

Main Results:

• Obese subjects exhibited significantly lower specific insulin binding (1.19 x 10(-2)) compared to normal subjects (1.92 x 10(-2)).
• No correlation was found between body weight and insulin receptors in obese individuals.
• Insulin receptor number negatively correlated with fat cell size and fasting plasma insulin.
• Fasting for 10 days increased insulin receptor numbers and normalized plasma insulin in obese subjects.

Conclusions:

• Obesity with hyperinsulinism is associated with a reduced number of insulin receptors.
• Decreased insulin receptor numbers may contribute to the reduced insulin sensitivity observed in hyperinsulinemic obese individuals.
• Fasting demonstrates a potential therapeutic avenue for improving insulin sensitivity in obesity.