In this pepar we investigated the developmental patterns of expression of growth hormone (GH) gene in pituitary tissue in pigs of different breeds and their effects on the carcass fat contents. 3 Jinhua gilts and 3 Landrace gilts were sampled at 35, 80 and 125 days of age, respectively. Carcass fat contents were determined. Pituitary tissue was sampled and total RAN was extracted to determine GH mRNA expression levels by semi-quantitative RT-PCR. The results showed that the contents of carcass fat increased with growth and showed significant differences (P﹤0.05) between different age groups in the two breeds. Furthermore, carcass fat contents in Jinhua gilts were higher than that in Landrace gilts during growth (P﹤0.05). GH mRNA expression levels decreased with age and displayed breed differences. Jinhua gilts showed lower abundance of GH mRNA compared with Landrace gilts at 35, 80 and 125 days of age (P﹤0.05). In addition, GH mRNA expression level was negatively related to carcass fat content in Jinhua and Landrace gilts (r = -0.790 (P = 0.01), r = -0.755 (P = 0.02), respectively).