But reality is not always so orderly. If the protons accumulate faster than small waterwheels can remove them, they seep through the membrane in other ways. And in skeletal muscle cells, this leakage of protons produces substantial amounts of heat. It is believed to help keep polar animals warm, said Traver Wright, a professor at Texas A&M University and author of the new article.
To see how many proton leaks could occur in sea otters, Dr Wright and his colleagues placed muscle cell samples from 21 animals in a special chamber that allowed researchers to monitor the ins and outs of the mitochondria of the sea otters. cells. They discovered that sea otters are capable of leaking huge amounts of protons, suggesting a substantial heat-producing capacity. And they were surprised to find that this ability was present in both small otters and adult adults.
In general, an organism’s metabolic capacity is related to its level of activity, Dr. Wright said. But young otters, of an age when they often relied on their mothers; adults of all sizes; and even a relatively inactive captive otter all had equally high metabolisms and great proton escape capacity. In fact, they had higher rates than even Iditarod sled dogs.
“Their escape metabolic rate is nowhere near as high as in sea otters,” Dr. Wright said of the dogs. For otters, he added, “this generation of heat is really the driving force behind their metabolic development.”
Sea otters consume calories even without much physical activity, as that energy converts directly into heat, the findings suggest. Otters are among the only animals to date where proton leakage can account for almost all of their high metabolism, Dr. Wright said.