Mice can detect the oxygen concentration in the air with their skin.
Reading Mice perceive low levels of oxygen in their skin. This is what American researchers found out in lab tests. Too little oxygen in the air led to an increased production of the hormone erythropoietin (EPO) in the kidneys of the animals and finally to a larger number of red blood cells, which transport oxygen in the blood. Thus, the mice can at least partially compensate for the effects of the low oxygen content. Amphibians such as frogs have long been known to sense oxygen through the skin. they sometimes even breathe through their skin. Certain ion channels are involved in this process, which researchers have now also detected in the skin of mice for the first time. In mammals, the existence of these channels has so far only been known in the lungs.

In order to check whether the skin of the mice is involved in the perception of oxygen, the scientists switched off a specific gene in the skin tissue of the animals. The product of this gene, HIF-1α, plays a major role in the body's response to hypoxia. The so-modified mice were exposed to an atmosphere of only ten percent oxygen, which is similar to the conditions a mouse would be exposed to on Mount Everest. Under these conditions, the production of the hormone EPO increased thirty-fold in normal mice, whereas it increased only slightly in genetically modified animals. Similarly, an increase in HIF-1α activity in the skin resulted in an increase in EPO production and hence in a higher number of red blood cells.

Also, by treating the skin with nitroglycerin, the researchers were able to stimulate EPO production in the mice. Nitroglycerin releases nitric oxide, which acts as a vasodilator. As a result, more blood flows to the skin, the kidneys? where is EPO produced? less. The researchers suspect that EPO production is stimulated by this mechanism.

"There is a great need for treatment with EPO in many diseases with low numbers of red blood cells, " says Randall Johnson, author of the study. "We show that even a small nitroglycerin patch can trigger a large increase in EPO production. Whether that also applies to humans, we do not know yet. "Display

Adam Boutin (University of California, San Diego) et al .: Cell, Vol. 133, p. 223 ddp / science.de? Michael Böddeker

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