Quantitative RT-PCR analysis of cardiac insulin-like growth factor (IGF). The mRNA expressions levels of IGF, IGF1R, IGF2 and IGFBP3 genes in the control, low calcium group (LCa), 25(OH)D3 group (VD) and low calcium + 25(OH)D3 group (LCa+VD) groups in the cardiac from piglets as determined by qRT-PCR. The data represent the mean ± SD.