TY - JOUR
T1 - The effect of vitamin D3 deficiency on the isolated chick heart
T2 - Hemodynamic, P-31 NMR and membrane studies
AU - Hochhäuser, Edith
AU - Kushnir, Tammar
AU - Navon, Gil
AU - Rehavi, Moshe
AU - Barak, Jacob
AU - Edelstein, Shmuel
AU - Vidne, Bernardo
PY - 1993/1
Y1 - 1993/1
N2 - The purpose of this study was to investigate whether vitamin D3 deficiency affects the cardiac function of chick hearts directly or whether the influence is secondary through the hormone's effect on serum calcium levels. To this end, three experimental groups were studied: (a) the control group of vitamin D3 supplemented chicks, D(s), (b) vitamin D3 deficient chicks, D(d), and (c) vitamin D3 supplemented hypocalcemie chicks raised on decreased calcium levels, D(h). The three groups were compared by checking hemodynamic, metabolic and membrane parameters. Total and ionized serum calcium concentrations in the D(h) and D(d) groups were found to be lower than in the D group. Perfusion of the isolated hearts with solutions containing various calcium concentrations (1, 1.5 and 2.5 mm) induced enhanced contractility levels, the magnitude of which was dependent on the difference between the in vivo and perfusate calcium levels. Thus, the inotropic effect was similar and more enhanced for the two hypocalcemic groups. The differences in hemodynamic behaviour could not be explained by variations in the levels of the high energy compounds and acidity, since similar ATP, creatine phosphate and intracellular pH levels were detected for both D(s) and D(d) groups. However, membrane studies revealed an increase in the number of slow calcium channels for the two hypocalcemic groups and this may be the possible mechanism for the differences in the contractile activity. In conclusion, our study strongly suggests that the effects of vitamin D3 on the heart is mediated only indirectly through its effect on serum calcium levels.
AB - The purpose of this study was to investigate whether vitamin D3 deficiency affects the cardiac function of chick hearts directly or whether the influence is secondary through the hormone's effect on serum calcium levels. To this end, three experimental groups were studied: (a) the control group of vitamin D3 supplemented chicks, D(s), (b) vitamin D3 deficient chicks, D(d), and (c) vitamin D3 supplemented hypocalcemie chicks raised on decreased calcium levels, D(h). The three groups were compared by checking hemodynamic, metabolic and membrane parameters. Total and ionized serum calcium concentrations in the D(h) and D(d) groups were found to be lower than in the D group. Perfusion of the isolated hearts with solutions containing various calcium concentrations (1, 1.5 and 2.5 mm) induced enhanced contractility levels, the magnitude of which was dependent on the difference between the in vivo and perfusate calcium levels. Thus, the inotropic effect was similar and more enhanced for the two hypocalcemic groups. The differences in hemodynamic behaviour could not be explained by variations in the levels of the high energy compounds and acidity, since similar ATP, creatine phosphate and intracellular pH levels were detected for both D(s) and D(d) groups. However, membrane studies revealed an increase in the number of slow calcium channels for the two hypocalcemic groups and this may be the possible mechanism for the differences in the contractile activity. In conclusion, our study strongly suggests that the effects of vitamin D3 on the heart is mediated only indirectly through its effect on serum calcium levels.
KW - 1,25(OH)D
KW - Chick heart
KW - P NMR
KW - Vitamin D deficiency
UR - http://www.scopus.com/inward/record.url?scp=0027339890&partnerID=8YFLogxK
U2 - 10.1006/jmcc.1993.1010
DO - 10.1006/jmcc.1993.1010
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AN - SCOPUS:0027339890
SN - 0022-2828
VL - 25
SP - 93
EP - 102
JO - Journal of Molecular and Cellular Cardiology
JF - Journal of Molecular and Cellular Cardiology
IS - 1
ER -