DIFFERENTIAL EXPRESSION OF THE GROWTH-HORMONE RECEPTOR AND ITS TRANSCRIPT IN BOVINE UTERUS AND PLACENTA

By reverse transcription-polymer-ase chain reaction (RT-PCR) the trans cript of the growth hormone receptor (GHR) was proved in bovine placen tae of different gestational stages. Using non-radioactive in situ hyb ridization (ISH) the mRNA encoding GHR was localized in the uterine ep ithelium, glands, vessels and amniochorion of the placenta from the si xth week until the ninth month of gestation. Production of mRNA was lo w during the first trimester, significantly increased in the second tr imester and peaked at the end of the sixth month of pregnancy. No tran script of GHR was found in the endometrium of non-pregnant uteri. The colocalization of the protein using a monoclonal antibody showed the s ame distribution pattern as the mRNA. Immunoblotting revealed a protei n with a molecular weight of 120 kDa in the endometrium of pregnant co ws which was not found in non-pregnant uteri. Our results imply that g rowth hormone is involved in placental metabolism and embryonic develo pment from the early beginning of pregnancy until birth. (C) 1997 Else vier Science Ireland Ltd.