Sixteen castrated male Large White × Landrace pigs were injected intramuscularly with recombinant porcine growth hormone (rpGH, 4 mg · d^-1, n=8) or saline (n=8) for 28 days. Animals were slaughtered 4 h after the final injection for tissue and blood sampling. RIA and semi-quantitative RT-PCR were employed for determining hormone and mRNA contents, respectively. rpGH administration enhanced average daily weight gain by 26.07% (P<0.05), elevated serum IGF-I concentration by 70.94% (P<0.01) but decreased serum level of leptin by 34.52% (P<0.01). The relative abundance of GH-R mRNA was increased by 24.45% (P<0.05) in liver, 50.66% (P<0.05) in adipose tissue, 21.29% (P<0.05) in semitendinosus (ST), but not in longissimus dorsi (LD) muscle. Coordinately, IGF-1 mRNA expression was enhanced by 45.30% (P<0.01) in liver, 27.82% (P<0.05) in adipose tissue, 41.04% (P<0.05) in ST, but not in LD muscle. The IGF-1 content in liver and ST were increased 2.97 and 5.53-fold, respectively. A significant (2.93-fold) increase of IGF-1 content was found in LD muscle too, uncoupling with the change in mRNA level. Moreover, rpGH administration augmented IGF-IR mRNA expression by 48.08% (P<0.01) whereas abated leptin mRNA expression by 28.19% (P<0.05) in adipose tissue. These results suggest that the effect of rpGH on GH-R and IGF-I gene expression is tissue-specific and rpGH administration may down-regulate leptin mRNA expression in adipose tissue either directly or via the mediation of local IGF-I/IGF-IR system.