The objective of this study was to determine if zinc, when added in combination with ractopamine hydrochloride (RH), would stabilize the interaction of RH with the <em>β</em>-adrenergic receptor, as indic...The objective of this study was to determine if zinc, when added in combination with ractopamine hydrochloride (RH), would stabilize the interaction of RH with the <em>β</em>-adrenergic receptor, as indicated by altered cAMP concentrations, mRNA quantity, or protein abundance. Cultured bovine skeletal muscle cells were established and treated after 120 h for 6, 24, and 96 h with differentiation media of specific treatments. Treatments were applied in a factorial arrangement with two levels of zinc (0 μM or 1 μM) and two levels of RH (0 μM or 10 μM) in differentiation media. cAMP levels were measured at 6, 24, and 96 h, while mRNA and protein were measured at 24 and 96 h. At 6 h, no differences (<em>P</em> > 0.05) were detected in cAMP levels between the treatments. However, at 24 h the 10 μM RH, 1 μM zinc treatment had the greatest concentrations of cAMP (<em>P</em> < 0.05). At 96 h the 10 μM RH, 0 μM zinc treatment had a lower concentration of cAMP (<em>P</em> = 0.05) compared to the control. No differences were detected in mRNA (<em>β</em>1-adrenergic receptor, <em>β</em>2-adenergic receptor, AMPKα, myosin heavy chain I, myosin heavy chain IIA, and myosin heavy chain IIX) concentrations between treatments. Protein quantity of the<em> β</em>1-adrenergic receptor and <em>β</em>2-adrenergic receptor did not differ between treatments. These results indicate that zinc, in combination with RH, may help sustain the RH response during prolonged exposure as indicated by increased cAMP concentrations.展开更多
The objective of this study was to determine if the addition of zinc (Zn) in combination with zilpaterol HCL (ZH) affected the interaction of ZH with the beta2-adrenergic receptor (<span style="white-space:now...The objective of this study was to determine if the addition of zinc (Zn) in combination with zilpaterol HCL (ZH) affected the interaction of ZH with the beta2-adrenergic receptor (<span style="white-space:nowrap;"><i></i></span><i>β<span style="white-space:nowrap;"></span></i>-AR) by altering cAMP production, gene expression, and protein abundance in cultured skeletal muscle cells. Cultures of muscle bovine satellite cells were established and treated at 120 h with: 1) 0 μM Zn/zilpaterol hydrochloride (ZH;<strong>CON</strong>);2) 0 μM Zn/10 μM ZH (<strong>ZH</strong>);3) 1 μM Zn from Zn chloride/0 μM ZH (<strong>Zn</strong>);4) 1 μM Zn from Zn chloride/10 μM ZH (<strong>ZN/ZH</strong>) in differentiation media for an additional 0, 6, 24, 48 and 96 h. Protein and mRNA were isolated and quantified at 24 and 96 h, and cAMP was measured at 0, 6, 24, 48 and 96 h. At 0, 24, 48 and 96 h, no differences (<i><span style="white-space:normal;">P</span></i> > 0.05) were detected in cAMP production. At 6 h, Zn cells had the greatest concentration of cAMP (<span style="white-space:nowrap;"><i></i></span><i>P<span style="white-space:nowrap;"></span></i> < 0.05) compared to ZH treatments. No differences (<i><span style="white-space:normal;">P</span></i> > 0.05) were detected in mRNA abundance at 24 h. At 96 h, 0 μM Zn/10 μM ZH cells had an increased abundance of myosin heavy chain (MHC)-I mRNA (<i><span style="white-space:normal;">P</span></i> < 0.05) compared to CON. Furthermore, ZH had a greater abundance of MHC-IIX mRNA (<i><span style="white-space:normal;">P</span></i> < 0.05) and a tendency for a greater abundance of IGF-1 mRNA (<span style="white-space:normal;"><i></i></span><i><span style="white-space:normal;">P</span><span style="white-space:normal;"></span></i> < 0.15) compared to CON and ZN/ZH. No differences (<i><span style="white-space:normal;">P</span></i> > 0.05) were detected in the protein abundance of <i><span style="white-space:normal;">β</span></i>1AR and the <i><span style="white-space:normal;">β</span></i>2AR. These results indicated Zn and ZH in combination did not have an additive effect on<em> β</em>2-AR function as indicated by cAMP concentrations.展开更多
文摘The objective of this study was to determine if zinc, when added in combination with ractopamine hydrochloride (RH), would stabilize the interaction of RH with the <em>β</em>-adrenergic receptor, as indicated by altered cAMP concentrations, mRNA quantity, or protein abundance. Cultured bovine skeletal muscle cells were established and treated after 120 h for 6, 24, and 96 h with differentiation media of specific treatments. Treatments were applied in a factorial arrangement with two levels of zinc (0 μM or 1 μM) and two levels of RH (0 μM or 10 μM) in differentiation media. cAMP levels were measured at 6, 24, and 96 h, while mRNA and protein were measured at 24 and 96 h. At 6 h, no differences (<em>P</em> > 0.05) were detected in cAMP levels between the treatments. However, at 24 h the 10 μM RH, 1 μM zinc treatment had the greatest concentrations of cAMP (<em>P</em> < 0.05). At 96 h the 10 μM RH, 0 μM zinc treatment had a lower concentration of cAMP (<em>P</em> = 0.05) compared to the control. No differences were detected in mRNA (<em>β</em>1-adrenergic receptor, <em>β</em>2-adenergic receptor, AMPKα, myosin heavy chain I, myosin heavy chain IIA, and myosin heavy chain IIX) concentrations between treatments. Protein quantity of the<em> β</em>1-adrenergic receptor and <em>β</em>2-adrenergic receptor did not differ between treatments. These results indicate that zinc, in combination with RH, may help sustain the RH response during prolonged exposure as indicated by increased cAMP concentrations.
文摘The objective of this study was to determine if the addition of zinc (Zn) in combination with zilpaterol HCL (ZH) affected the interaction of ZH with the beta2-adrenergic receptor (<span style="white-space:nowrap;"><i></i></span><i>β<span style="white-space:nowrap;"></span></i>-AR) by altering cAMP production, gene expression, and protein abundance in cultured skeletal muscle cells. Cultures of muscle bovine satellite cells were established and treated at 120 h with: 1) 0 μM Zn/zilpaterol hydrochloride (ZH;<strong>CON</strong>);2) 0 μM Zn/10 μM ZH (<strong>ZH</strong>);3) 1 μM Zn from Zn chloride/0 μM ZH (<strong>Zn</strong>);4) 1 μM Zn from Zn chloride/10 μM ZH (<strong>ZN/ZH</strong>) in differentiation media for an additional 0, 6, 24, 48 and 96 h. Protein and mRNA were isolated and quantified at 24 and 96 h, and cAMP was measured at 0, 6, 24, 48 and 96 h. At 0, 24, 48 and 96 h, no differences (<i><span style="white-space:normal;">P</span></i> > 0.05) were detected in cAMP production. At 6 h, Zn cells had the greatest concentration of cAMP (<span style="white-space:nowrap;"><i></i></span><i>P<span style="white-space:nowrap;"></span></i> < 0.05) compared to ZH treatments. No differences (<i><span style="white-space:normal;">P</span></i> > 0.05) were detected in mRNA abundance at 24 h. At 96 h, 0 μM Zn/10 μM ZH cells had an increased abundance of myosin heavy chain (MHC)-I mRNA (<i><span style="white-space:normal;">P</span></i> < 0.05) compared to CON. Furthermore, ZH had a greater abundance of MHC-IIX mRNA (<i><span style="white-space:normal;">P</span></i> < 0.05) and a tendency for a greater abundance of IGF-1 mRNA (<span style="white-space:normal;"><i></i></span><i><span style="white-space:normal;">P</span><span style="white-space:normal;"></span></i> < 0.15) compared to CON and ZN/ZH. No differences (<i><span style="white-space:normal;">P</span></i> > 0.05) were detected in the protein abundance of <i><span style="white-space:normal;">β</span></i>1AR and the <i><span style="white-space:normal;">β</span></i>2AR. These results indicated Zn and ZH in combination did not have an additive effect on<em> β</em>2-AR function as indicated by cAMP concentrations.