Monoclonal antibody enhancement of the effects of human growth hormone on growth and body composition in mice.

Dwarf mice were treated for 10 days with phosphate-buffered saline (PBS), human growth hormone (hGH) or hGH with monoclonal antibody EB1 (hGH/MAB-EB1); for each treatment there were three groups which received 50, 75 or 100% of the amount of food eaten when available ad libitum. The PBS control groups lost more or gained less weight than equivalent groups receiving hGH alone, and mice given hGH/MAB-EB1 showed a greater weight gain than those in comparable groups receiving hGH alone. When weight gain or loss was expressed as g/g food eaten, groups treated with hGH gained more or lost less than the PBS groups. Similarly, weight gain/g food was significantly greater in hGH/MAB-EB1 animals than in the comparable groups given hGH alone. A similar pattern of response was observed for increases in tail length and uptake of 35SO42- into costal cartilage in vivo. For mice given hGH alone, fat content was decreased compared with that in the equivalent group given PBS, and mice treated with hGH/MAB-EB1 had less fat than the equivalent group given hGH alone. Administration of hGH alone caused a concomitant increase in protein content and body weight such that, compared with mice given PBS, there was no significant increase in protein as a proportion of body weight. However, hGH/MAB-EB1 caused an increase in whole body protein which was significantly greater than that for the equivalent group given hGH alone, when expressed as per cent body weight. Monoclonal antibody EB1 has been shown to enhance the actions of hGH on growth and body composition in Snell dwarf mice and to increase food conversion efficiency.