Ractopamine

Ractopamine (LY031537 free base) is a potent and orally active β-adrenergic receptor (βAR) agonist with K_d value of ~25 nM for pig β1AR and β2AR. Ractopamine also is a mTAAR1 agonist with an EC₅₀ of 16 μM. Ractopamine promotes muscle mass development, limits fat deposition, reduces feed consumption, increases total cellular protein synthesis, and improves growth rate and feed efficiency in finishing swine. Ractopamine can be used for researching to increase lean tissue growth and improve production efficiency in pigs^{[1][2][3][4][5]}. IC50 & Target:β-Adrenergic receptor^[1] In Vitro:Ractopamine (50 nM-100 μM) acts as a full agonist of mouse trace amine-associated receptor 1 (mTAAR1) in Xenopus laevis oocytes coexpressing hCFTR and mTAAR1, with an EC₅₀ of 16 μM, via a cAMP-dependent pathway^[1].
Ractopamine increases protein accumulation and synthesis in postfusion ELC₅ myotubes in a concentration-dependent manner^[3].
Ractopamine shows K_d value of ~25 nM for pig β1AR and β2AR^[5]. In Vivo:Ractopamine (5-10 mg/kg; oral; divided into 3 daily portions; 28 days) supplementation in finishing pigs causes minimal changes to specific behaviors, no changes to stress-related cortisol or lactate levels or skin/carcass lesions, but doubles serum creatine kinase concentrations, indicating potential muscular effects^[2].
Ractopamine (5-20 mg/kg; p.o.; daily; 48 days) administered in the diet of finishing swine linearly improves average daily gain, increases carcass weight and loin eye are^[4].