Prostatic GHR in TAg/Gh+/+ rats increased significantly during carcinogenesis. A, Quantitative RT-PCR analysis of GHR mRNA expression in the lateral prostates of TAg/Gh+/+ rats relative to cancer-free, age-matched non-TAg controls. The levels of GHR mRNA during carcinogenesis in TAg/Gh+/+ rats are presented relative to GHR mRNA levels in age-matched, cancer-free (no TAg oncogenic transgene, Gh+/+) prostates, which were assigned a value of 100%. *, Significantly different from age-matched non-TAg control (P < 0.01). B–D, IHC analysis of prostate GHR expression in TAg/Gh+/+ rats during prostate cancer progression at 10, 25, or 52 wk of age. E–G, IHC analysis of prostate GHR expression in Gh+/+ rats at 10, 25, or 52 wk of age.