Insulin is a prandial satiety hormone

Area of Science:

• Endocrinology
• Neuroscience
• Behavioral Science

Background:

• Understanding the role of insulin in regulating food intake is crucial for metabolic health.
• Previous research suggests a link between insulin and appetite control, but specific mechanisms remain under investigation.

Purpose of the Study:

• To investigate the effects of meal-contingent insulin administration on spontaneous meal patterns in rats.
• To determine if insulin functions as a prandial satiety hormone.

Main Methods:

• Rats were trained to lever press for food, establishing stable meal patterns.
• Hepatic-portal catheters were implanted for insulin or saline infusions during meals.
• Dose-dependent effects of insulin (1-2 mU) on meal size and other parameters were assessed.
• A complementary study examined meal size changes after exposure to diazoxide, a drug that limits insulin release.

Main Results:

• Administration of insulin (1 mU and 2 mU) significantly reduced spontaneous meal size in rats (p < .01 and p < .001, respectively).
• No other meal parameters, such as meal frequency or duration, were significantly affected by insulin.
• Rats recovering from diazoxide exposure exhibited increased meal sizes, indicating a role for insulin in limiting food intake.

Conclusions:

• Insulin acts as a prandial satiety hormone, reducing food intake when administered during spontaneous meals.
• The findings suggest that insulin promotes satiety by increasing glucose uptake into peripheral tissues.
• Pharmacological interventions affecting insulin release directly impact meal size regulation.