Effect of chronic GH treatment on body weight gain. WT and null ALS mice (null) were treated twice daily with GH (3 μg/g body weight per injection) or an equivalent volume of saline from 35 to 63 d of age. A, Body weights were recorded daily and the cumulative gain calculated by difference from body weight on d 30. The arrow indicates the start of treatment. Data are shown for female and male mice. B, The cumulative weight gain during the treatment period was calculated as the difference between weight on d 63 and 35. Data are shown for female and male mice. C, GH-stimulated gain in female mice. This variable corresponds to the gain, depending exclusively on exogenous GH, and was calculated for the entire treatment period by subtracting the average gain of saline-treated mice from the gain of each GH-treated mice. The significant effects of G (WT or null), H (saline or GH), and their interaction (G × H) are reported. Each line and bar represents means of seven to nine mice.