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. Author manuscript; available in PMC: 2013 Dec 1.
Published in final edited form as: J Muscle Res Cell Motil. 2012 Jun 30;33(6):431–437. doi: 10.1007/s10974-012-9310-0

Figure 5.

Figure 5

Treatment of rats with propyl-thiouracil (PTU) induces hypothyroidism that leads to the gradual replacement over several weeks of α- by β-myosin (MHC) in the heart (top panel). There is a direct proportional relationship between the myosin composition and various mechano-energetic parameters such as the ATPase activity during maximum isometric force development (ATPasemax), the ratio of ATPase activity and force development (tension-cost), the rate of force redevelopment following a sarcomere length perturbation (ktr), and the maximum unloaded velocity of sarcomere shortening (VSLmax). Modified from (de Tombe and ter Keurs, 1991a; Rundell et al., 2005). The 100% level of the various parameters is indicated by the solid hexagonal: ATPasemax = 600 pmol/s; tension-cost = 10 pmol/s/mm3; Ktr = 16/s; VSLmax = 15 μm/s.