GH1 and hypopituitarism: Evidence for the ability of GH to influence healthspan and lifespan of laboratory mice is very strong and includes significant extension of longevity in both sexes of mice with hypopituitarism (combined deficiency of GH, prolactin, and TSH) (Brown-Borg et al., 1996; Flurkey et al., 2001), in mice with isolated GH deficiency due to mutation of Ghrhr gene or deletion of Ghrh (Flurkey et al., 2001; Sun et al., 2013), and in mice with GH resistance due to Ghr gene disruption (Zhou et al., 1997; Coschigano et al., 2003).