GH Action in Prostate Cancer Cells Promotes Proliferation, Limits Apoptosis, and Regulates Cancer-related Gene Expression.

Previous studies investigating the effects of blocking the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis in prostate cancer found no effects of the growth hormone receptor (GHR) antagonist, pegvisomant, on the growth of grafted human prostate cancer cells in vivo. However, human GHR is not activated by mouse GH, so direct actions of GH on prostate cancer cells were not evaluated in this context. The present study addresses the species specificity of GH-GHR activity by investigating GH actions in prostate cancer cell lines derived from a mouse Pten-deletion model.

Mammary Tumors Growing in the Absence of Growth Hormone Are More Sensitive to Doxorubicin Than Wild-Type Tumors.

Previously, we reported that N-methyl-N-nitrosourea (MNU)-induced mammary tumors could be established in mutant spontaneous dwarf rats (SDRs), which lack endogenous growth hormone (GH) by supplementing with exogenous GH, and almost all such tumors regressed upon GH withdrawal. When the highly inbred SDR line was outcrossed to wild-type (WT) Sprague-Dawley rats, MNU-induced mammary tumors could still be established in resulting outbred SDRs by supplementing with exogenous GH. However, unlike tumors in inbred SDRs, 65% of mammary tumors established in outbred SDRs continued growth after GH withdrawal.