Localization of growth hormone receptor messenger RNA in human tissues.

In order to identify GH target cells in human tissues, we investigated the celiuiar distribution of human GH receptor (GHR) messenger RNA. This was performed byin situ hybridization and Northern blot hybridization using complementary radioactive DNA probe encoding part of the extracellular domain of the GHR. Several tests were carried out to validate the detection of gene expression. Our results demonstrate that the GHR gene is expressed in all human tissues studied, including liver, muscle, kidney, heart, skin, thymus, adipose tissue, placenta, testis, ovary and mammary gland. The quantification of thein situ hybridization signal by densitometric analysis showed a greater expression of GHR transcript in liver, muscle, kidney, heart, and skin epidermis, and a reduced expression in thymus, mammary gland, testis, ovary, and dermis/ hypodermis. These results confirm the widespread distribution of the GHR gene expression in human tissues and identify the cells that might be responsive to GH.