Hypothesis: Musculin is a hormone secreted by skeletal muscle, the body’s largest endocrine organ
Keywords:
Musculin, skeletal muscle hormone, exercise, pancreatic beta cell, hypothalamus, growth hormone, adrenocorticotropin, prolactinAbstract
Recent studies indicate that skeletal muscle may act as an endocrine organ by secreting interleukin-6 (IL-6) into the systemic circulation. From an analysis of the actions of IL-6 and of additional literature, we postulate that skeletal muscle also secretes an unidentified hormone, which we have named Musculin (Latin: musculus = muscle), which acts on the pancreatic b-cell to restrain the size of the b-cell mass and to tonically inhibit insulin secretion and biosynthesis. It is suggested that the amount of Musculin secreted is determined by, and is positively correlated with, the prevailing insulin sensitivity of skeletal muscle, thereby accounting for the hyperinsulinemia that occurs in insulin resistant disorders such as type 2 diabetes mellitus, obesity, and the polycystic ovary syndrome. In addition, it is postulated that Musculin acts on the hypothalamus (arcuate nucleus, dorsomedial hypothalamic nucleus) to co-ordinate the neuroendocrine and appetite responses to exercise. However, the possibilities that Musculin may act on additional central nervous system sites and that an additional hormone(s) may be responsible for these actions are not excluded. It is suggested that a search be made for Musculin, since analogues of such a substance may be of therapeutic benefit in the treatment of the current global diabetes and obesity epidemic.Downloads
Published
Issue
Section
License
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Transfer of Copyright and Permission to Reproduce Parts of Published Papers.
Authors retain the copyright for their published work. No formal permission will be required to reproduce parts (tables or illustrations) of published papers, provided the source is quoted appropriately and reproduction has no commercial intent. Reproductions with commercial intent will require written permission and payment of royalties.