(en) In rat three myosin heay chains were observed with apparent molecular weights of 204 kDa (MHC 204), 207 kDa (MHC 207) and in termediate (MHC IM), between 204 and 207 kDa. Their relative proportions depends on the age of the rats
Yuksel, D., & Maréchal, G. (1991). Post-natal changes of myosin heavy chains in rat uterus. Journal of Muscle Research and Cell Motility, 12(1), 85. https://hdl.handle.net/2078.5/215349 (Original work published 1991)