GH, short for growth hormone, is a peptide hormone. It can signal directly via its receptor or indirectly through insulin-like growth factor 1 (IGF-1) stimulation. GH is well-known for its anabolic effects on muscle and bone, and also has metabolic effects in multiple tissues. It is closely associated with processes like aging, and its action is related to lifespan [1].

In GH gene-disrupted (GH-/-) mice, there are severely decreased IGF-1 levels, small body size, and altered body composition with increased adiposity. These mice are extremely insulin-sensitive but glucose-intolerant, with a reduced pancreatic islet size. GH-/-mice also show depot-specific effects on white adipose tissue, with subcutaneous WAT having larger adipocytes and reduced fibrosis [4].

In conclusion, GH is fundamental for skeletal growth during puberty and bone health throughout life. It also impacts cardiac growth, myocardial contractility, and the vascular system. The study of GH-/-mice has provided insights into the role of GH in body composition, insulin sensitivity, and adipose tissue fibrosis, which are relevant to understanding diseases related to growth, metabolism, and aging [1,2,3,4].

References:

1. Young, Jonathan A, Zhu, Shouan, List, Edward O, Slama, Yosri, Berryman, Darlene E. 2022. Musculoskeletal Effects of Altered GH Action. In Frontiers in physiology, 13, 867921. doi:10.3389/fphys.2022.867921. https://pubmed.ncbi.nlm.nih.gov/35665221/

2. Locatelli, Vittorio, Bianchi, Vittorio E. 2014. Effect of GH/IGF-1 on Bone Metabolism and Osteoporsosis. In International journal of endocrinology, 2014, 235060. doi:10.1155/2014/235060. https://pubmed.ncbi.nlm.nih.gov/25147565/

3. Arcopinto, Michele, Bobbio, Emanuele, Bossone, Eduardo, Sacca, Luigi, Cittadini, Antonio. . The GH/IGF-1 axis in chronic heart failure. In Endocrine, metabolic & immune disorders drug targets, 13, 76-91. doi:. https://pubmed.ncbi.nlm.nih.gov/23369140/

4. List, Edward O, Berryman, Darlene E, Buchman, Mathew, McKenna, Savannah, Kopchick, John J. . GH Knockout Mice Have Increased Subcutaneous Adipose Tissue With Decreased Fibrosis and Enhanced Insulin Sensitivity. In Endocrinology, 160, 1743-1756. doi:10.1210/en.2019-00167. https://pubmed.ncbi.nlm.nih.gov/31099824/