Dibutoxybutane Suppresses Protein Degradation and Promotes Growth in Cultured Chicken Muscle Cells

抄録

Dibutoxybutane (DBB) is a possible growth promoter contained in shochu distillery by-product. In the present study, we synthesized DBB in order to confirm the growth promoting action. After determining the chemical structure of the synthetic product by nuclear magnetic resonance and gas chromatography mass spectrometry, an experiment was conducted using chicken skeletal muscle cells. DBB was mixed with the culture medium at the level of 0, 0.015, 0.15, 1.5, 15 and 150 μg/ml and cells derived from thigh muscle of 13-day-old chick embryos were raised for 6 days. The muscle cell growth was accelerated and the rate of protein degradation estimated from N^τ-methylhistidine release into the medium was decreased by DBB. Furthermore, the mRNAs of muscle-specific E3 ubiquitin ligases, atrogin-1/MAFbx and MuRF1, were decreased by DBB. However, mRNAs of ubiquitin, proteasome C2 subunit and μ-calpain were not affected by DBB. Activities of chicken’s two ubiquitous μ- and μ/m-calpain which were quantified by casein zymography were decreased by DBB. These results show that DBB promotes muscle growth due to a decrease in the rate of protein degradation.