Peripheral tissues showed diverse evidence of chronic lack of GH stimulation: Liver GH receptors were hypersensitive to GH stimulation (Figure 4C), and several markers of peripheral GH action were abnormally low in adults (IGFBP-3, −37%; ALS, −53%; Figure 4D; serine protease inhibitor Spi2.1, −53%, unpublished data). This evidence concerns the gene GHR and amyotrophic lateral sclerosis.