Potent and selective human beta(3)-adrenergic receptor antagonists

Area of Science:

• Pharmacology
• Adrenergic Receptor Research
• Human Physiology

Background:

• The role of beta(3)-adrenergic receptors (beta(3)-AR) in human adipose tissue remains debated due to a lack of selective human ligands.
• Previous research established beta(3)-AR function in rodents but faced challenges in human studies.

Purpose of the Study:

• To develop and characterize novel, selective antagonists for the human beta(3)-AR.
• To provide tools for investigating human beta(3)-AR function in metabolic processes like lipolysis.

Main Methods:

• Synthesis of novel aryloxypropanolamine benzenesulfonamide derivatives.
• Binding affinity assays for human beta(3)-AR, beta(1)-AR, and beta(2)-AR.
• Functional assays measuring lipolysis inhibition in isolated adipocytes.

Main Results:

• L-748,328 and L-748,337 demonstrated high affinity for human beta(3)-AR (3.7-4.0 nM) with significant selectivity over beta(1)-AR and beta(2)-AR.
• These compounds acted as competitive antagonists, inhibiting agonist-induced activation of human beta(3)-AR.
• Both antagonists effectively inhibited lipolysis in nonhuman primate adipocytes stimulated by a beta(3)-AR agonist.

Conclusions:

• Novel aryloxypropanolamine benzenesulfonamides serve as potent and selective antagonists for the human beta(3)-AR.
• Specific structural modifications, such as 3'-phenoxy substitutions, can convert agonists into antagonists.
• These selective antagonists are valuable tools for studying human beta(3)-AR pharmacology and its role in metabolism.