Table 2.

Relative ventricle mass and enzyme activities in the compact and spongy myocardial layers of three lamniform shark species

Enzyme activity a at 20°C
Species (common name)Body mass (kg)Relative ventricle mass (% body mass)Relative compact myocardial tissue (% of ventricle)CompactSpongy *CompactSpongy
Isurus oxyrinchus 6∼0.17 b,c∼36-40 b,d37.744.0494503
(shortfin mako shark)2639.942.8487495
Lamna ditropis 1270.18-0.20 c∼40 d34.538.0306312
(salmon shark)13631.632.7409428
Alopias vulpinus 21−0.10-0.29 b∼36 b32.631.4459487
(common thresher shark)3425.231.7421499
  • a Enzyme activities are expressed as μmol substrate converted to product per min (IU) per g wet mass of tissue.

  • b Data from Emery et al. (1985).

  • c D. Bernal, N. C. Lai, W. Lowell, K. Dickson, C. Sepulveda and J. Graham, unpublished.

  • d D. Bernal and J. Graham, unpublished.

  • * Spongy myocardium CS activities are significantly higher (P<0.05) than in compact myocardium.