Comparison of skeletal growth in normal and "little" mice

The relationship of skeletal weight to body weight was compared in the C57BL/6J mouse strain and a spontaneously-derived mutant, "little" (gene symbol lit). The lit/lit mouse is characterized by reduced size for age and pituitary deficiency of growth hormone. Cleaned skeletons were obtained from skinned, eviscerated carcasses of the two mouse types by exposing them to a colony of Dermestes maculatus beetles and larvae. Regression analysis of the data indicated that an allometric relationship existed between skeletal weight and body weight for each group of mice. The regression equation obtained for female C57BL/6J mice was comparable with that obtained for female lit/lit mice. Similarly, the regression equations for male C57BL/6J and lit/lit mice were nearly identical to each other, although the slopes of the regression lines were slightly less than for the female mice. These data demonstrate that colonies of D. maculatus may be usefully employed to compare skeletal growth patterns in mice and indicate that there is no significant difference in the relationship of skeletal weight to body weight when C57BL/6J mice are compared with lit/lit mice of the same sex.