Acute Treatment With XMetA Activates Hepatic Insulin Receptors and Lowers Blood Glucose in Normal Mice

Area of Science:

• Metabolic diseases
• Pharmacology
• Immunology

Background:

• Monoclonal antibodies show therapeutic potential for metabolic diseases like diabetes mellitus.
• XMetA, an allosteric monoclonal antibody to the human insulin receptor (IR), activates metabolic signaling and lowers glucose in preclinical models.
• The tissue distribution of large molecules like antibodies may differ, impacting their acute effects.

Purpose of the Study:

• To compare the acute effects of XMetA and insulin on glucose lowering and insulin receptor activation in key insulin-sensitive tissues.
• To investigate the tissue-specific mechanisms of XMetA's glucose-lowering action in normal fasted mice.

Main Methods:

• Intravenous administration of XMetA (10 mg/kg) and insulin (0.5 U/kg) to normal fasted mice.
• Comparison of blood glucose levels, insulin receptor (IR) and Akt phosphorylation in liver, adipose, and muscle tissues over 90 minutes.
• Measurement of plasma β-hydroxybutyrate, non-esterified fatty acids (NEFA), and glycerol.

Main Results:

• Both XMetA and insulin reduced blood glucose levels, with XMetA showing a less rapid onset.
• Insulin activated IR and Akt phosphorylation in liver, adipose, and muscle tissues.
• XMetA-induced IR activation was predominantly observed in the liver, while both agents lowered β-hydroxybutyrate; only insulin reduced NEFA and glycerol.

Conclusions:

• In normal mice, acute glucose regulation by the monoclonal antibody XMetA is primarily mediated by its effects on the liver.
• XMetA demonstrates tissue-specific activity, distinct from insulin's broader systemic effects in the acute phase.