Irisin and parathyroid hormone are linked in primary hyperparathyroidism

Irisin is considered a molecule with hormone function mainly secreted by muscle after physical activity but variably produced by many tissues such as skeletal muscle, heart and liver. Irisin produces several effects on bone mineral density (BMD), stimulating osteoblast (bone forming cells) activity with increase of the cortical bone. On the counterpart, parathyroid hormone (PTH) seems to act on the opposite way, since in endocrine diseases, such as primary hyperparathyroidism, the prolonged action of elevated pathological PTH blood levels causes a BMD reduction. In a recent paper published on The Journal of Clinical Endocrinology & Metabolism, two members of the ECTS Academy, Andrea Palermo and Graziana Colaianni, investigated on the possible molecular relationship between Irisin and PTH. As a first step, by “in vitro experiments”, they were able to prove that the two hormones inhibit one each other: high PTH levels repress the secretion of Irisin molecule in mouse muscle cells. On the other hand, Irisin treatment is able to reduce the production of PTH in the osteoblasts, thus blocking its action. Moreover, as second step, they found that in patients affected by primary hyperparathyroidism condition (having chronic high PTH), Irisin blood levels are reduced up one third compared to controls. These novel findings shed light on the complex crosstalk between these two hormones, and suggest that a similar inverse functional correlation might exists also for other tissues, such as fat and muscle.

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