Expression of cyclooxygenases (Cox) 1 and 2 in liver of mice chronically exposed to elevated levels of growth hormone (GH)

VALQUINTA S; PIAZZA VG; SOTELO AI ; CICCONI N; FRUNGIERI MB; MATZKIN ME; GONZALEZ L ; MIQUET JG

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sociedad Argentina de Investigación Clínica

Transgenic mice overexpressing GH exhibit high incidence of liver tumors, including hepatocellular carcinoma, and display of the cyclooxygenases. High levels of these enzymes have been associated with carcinogenesis processes in different tissues. We have previously found that the protein content of COX1 was increased in the liver of transgenic mice overexpressing GH. Therefore, the first objective of the present work was to assess the protein levels of COX2 in hepatic tissue from these animals. Considering that transgenic mice are continuously exposed to high GH levels since birth, as a second objective we pursued to determine if the administration of GH to control mice in lower concentration modifies the hepatic expression of the cyclooxygenases, and if the effect depends on the administration pattern (intermittent vs. continuous). Forthat purpose, GH was administered (6 mg/Kg/day) to Swiss-Webster mice for 5 weeks (from 3 to 8 weeks of life) by means of two subcutaneous injections per day or by implantation of mini-osmotic pumps for continuous deliver. The protein levels of COX1 and COX2 were determined by immunoblotting and immunohistochemistry assays. As previously observed for COX1, COX2 hepatic levels were higher in transgenic mice than in normal controls, both in males andfemales (p