The Siberian frog survives in water with an almost complete absence of oxygen for up to six months and retains the ability to move, while the moor frog and salamander remain on land in the upper layers of the soil and, when frozen, experience severe hypoxia due to the cessation of blood circulation, the scientists said.
Biologists studied the metabolome (a set of small molecules in the body) of these amphibians and found that by autumn, animals accumulate glycogen in the liver, a polysaccharide that breaks down into glucose and glycerol in winter. They provide energy to the cells of the body before freezing, and then act as antifreeze.
“In a state of hypoxia / freezing in frogs and salamander, scientists discovered ethanol (that is, etiol alcohol – Approx. ed.), which has never before been observed in such numbers in terrestrial vertebrates. The discovery of 2,3-butanediol, a molecule that is often found in metabolomic studies of vertebrates, but its function remains unknown, also seemed interesting.