Findings for postmenopausal women remained unclear and needed additional studies [47]. Lee et al. the part of thyroid hormones on bone metabolism. Keywords: Thyroid hormones, Thyroid diseases, Osteoporosis, Fractures == Introduction == A lot of different factors are necessary to fix and harmonious development as well as normal functioning of skeleton: genetic conditions, hormonal and metabolic homeostasis, balanced diet, mechanical insert [1]. Any disturbances of those real estate agents can lead to serious and harmful consequences like length reduction, deformations, fractures. Their results depend, between other, on ones era, type of disorder and its period. We dont have any influence on some of mentioned before factors, yet part from them is possible to modify. It is very significant because abnormalities and irregularities of bone tissue mineralization can lead to loss of bone tissue density and to osteoporosis in final effect [1]. Because of rising number of newly diagnosed osteoporosis cases it is necessary to perform the investigation for all those potential secondary conditions which could lead to reduced bone mineral density. It is crucial because osteoporotic fractures are directly related with dropped quality of life, disability and mortality. It is estimated that 40% of women and 13-22% of men aged about 50 will certainly experience to the end of life at least 1 fracture connected with osteoporosis primarily proximal femur, spine or forearm [2]. Societys aging causes that the number of people with osteoporotic fracture in Poland will certainly amount in year 2025 about several. 23 large numbers. It means growth about 32. 8% relatively to season 2008. Besides, unfortunately a trend appeared that osteoporosis, mainly secondary, is diagnosed in more and more younger age groups. There is a large amount of endocrinological reasons of secondary osteoporosis (for example: Cushing’s syndrome, hyperparathyroidism, hypogonadism, acromegaly, diabetes mellitus etc . ) [3]. It is necessary to remember about them because their adverse influence on bone cells is potentially reversible. In this group also thyroid glandular hormonal disorders play an essential role. Human being interest about the influence of thyroid hormone on skeleton continues since very long time. Von Recklinghausen described a correlation between numerous fractures and condition of hyperthyroidism over 120 IPI-493 years ago [4]. Researches and conversations persist if the key part on bone tissue tissue provides TSH or thyroid hormones? Is this query important? The answer is yes, because disorders of thyroid glandular and disturbances of axis TRH-TSH-fT3 and fT4 are very often; concern millions EIF2Bdelta of people in global level. The implications for bone tissue leading to bone tissue loss causes that willingness of the response to the question about the influence of thyroid dysfunction on bone is very great. == Review == == Molecular actions of thyroid hormones in bone tissue tissue == The action of thyroid hormones is usually mediated by thyroid hormone receptors (TR), which are encoded by THRA and THRB genes [4]. Each of TR owns a couple of subtypes. We can differ TR1, TR2, TR1, TR2 receptors [5-7]. They are localized not only on thyrocytes, yet also on majority human being tissues and cells. Only TR2 is usually connected with hypothalamus and pituitary, where inhibits the secretion of TRH and TSH [8, 9]. Their particular expression in bone directly means that this tissue is usually under the IPI-493 influence of thyroid hormones. Osteoblasts and chondrocytes exert the expression of both TR and TR IPI-493 [5, 6, 10], yet concentration of TR1 is usually ten occasions larger than TR1 [4, 5]. TR1 is considered like a main functional mediator of triiodothyronine in skeleton [5, eleven, 12]. The biological part of TR2 is unfamiliar [13]. Deficiency or dysfunction of TR contributes to IPI-493 growth retardation, delayed bone tissue age, perturbations in bone tissue mineralisation and decreased BMD [8, 14]. T3 regulates the chondrogenesis and bone mineralisation [6]. T3 induces the IL-6 and IL-8, intensifies the effects of IL-1 and IL-6, augments the synthesis of osteocalcin, collagen type 1, boosts proliferation, differentiation and apoptosis of osteoblasts [8]. The receptors for TSH (TSHR) are located not only in thyroid follicular cells, but also in osteoblasts and osteoclasts [4, 5]. Data from medical reports shows that TSH is considered like a negative regulator of bone tissue turnover [4]. Its direct action on bone tissue tissue cells leads to enhanced bone remodeling and osteoporosis [15, 16]. == The influence of overt hyperthyroidism on bone == Thyroid hormones play pivotal role in linear development of skeleton. They may be necessary to accomplish peak bone tissue mass [8]. But the excess of thyroid hormones in childhood can lead to premature accretion of growth plates and cranial sutures and lastly short stature and craniosynostosis [8, 13, 17, 19]. In adults, overt hyperthyroidism leads to speed.