Interactions between growth hormone and dexamethasone in skeletal growth and bone structure of the young mouse.

The present study investigated the interactions of growth hormone (GH) and glucocorticoid on skeletal growth and bone structure in young mice. The purpose of this study was to examine the possible prevention by GH of the damage inflicted by dexamethasone (Dex) at sites of skeletal growth and ossification. Dex (1 mg/kg) with or without rat GH (rGH) or bovine GH (bGH), 1 mg/kg, was given for 4 weeks, from age 3-7 weeks, to female ICR mice. Tibiae, humerus, and vertebrae were analyzed morphometrically and biochemically. Growth, as determined by the mouse weight, tibial length, and humerus protein content was found to be compromised by dexamethasone. This was prevented by rGH or bGH. The epiphyseal growth plate width, trabecular bone volume, cortical bone width, mineral bone content, and alkaline and acid phosphatase activity were decreased by dexamethasone. These were prevented by rGH or by bGH. The findings of the present study suggest that in the mouse, GH can decrease or even avoid some of the pathological features in growing bones inflicted by high-dose glucocorticoid treatment.