A frozen frog embodies an unusual biological structure. It
shows no signs of life. Its heartbeat, breathing and blood circulation have come
completely to a halt. When the ice melts, however, the same frog returns to life as if it
is has woken up from sleep.
Normally, a living being in the state of freezing confronts many fatal
risks. The frog, however, does not face any of them. It has the main feature of producing
plenty of glucose while it is in that state. Just like a diabetic, the blood sugar level
of the frog reaches very high levels. It can sometimes go as high as 550 milimol/liter.
(This figure is normally between 1-5 mmol/litre for frogs and 4-5 mmol/litre for human
body). This extreme glucose concentration may cause serious problems in normal times.
In a frozen frog, however, this extreme glucose keeps water from
leaving cells and prevents shrinkage. The cell membrane of the frog is highly permeable to
glucose so that glucose finds easy access to cells. The high level of glucose in the body
reduces the freezing temperature causing only a very small amount of the animals
inner body liquid to turn to ice in the cold. Research has showed that glucose can feed
frozen cells as well. During this period, besides being the natural fuel of the body,
glucose also stops many metabolic reactions like urea synthesis and thus prevents
different food sources of the cell from being exhausted.
How does such a high amount of glucose in the frogs body come
about all of a sudden? The answer is quite interesting: this living being is equipped with
a very special system in charge of this task. As soon as ice appears on the skin, a
message travels to the liver making the liver convert some of its stored glycogen into
glucose. The nature of this message travelling to the liver is still unknown. Five minutes
after the message is received, the sugar level in the blood steadily starts to increase.
Unquestionably the animals being equipped with a system that
entirely changes its metabolism to meet all of its needs just when it is required can only
be possible through the flawless plan of the All-Mighty Creator. No coincidence can
generate such a perfect and complex system.