kilpnäärmehormoonasendus

kilpnäärmehormoonid are hormones produced and secreted by the thyroid gland, a small butterfly-shaped gland located in the neck. The primary thyroid hormones are thyroxine (T4) and triiodothyronine (T3). T3 is the more potent and biologically active form. These hormones are essential for regulating metabolism in virtually every cell in the body.

The synthesis of kilpnäärmehormoonid begins with iodine, which is absorbed from the diet and transported to the thyroid gland. Within the thyroid, iodine is incorporated into tyrosine, an amino acid, to form monoiodotyrosine (MIT) and diiodotyrosine (DIT). These iodinated tyrosines are then coupled to form T3 and T4. The thyroid gland stores these hormones within a protein called thyroglobulin.

The release of kilpnäärmehormoonid into the bloodstream is regulated by the pituitary gland, which secretes thyroid-stimulating hormone (TSH). TSH stimulates the thyroid gland to produce and release T4 and T3. In turn, the levels of T4 and T3 in the blood influence the pituitary gland's secretion of TSH through a negative feedback loop. High levels of T4 and T3 suppress TSH release, while low levels stimulate it.

Kilpnäärmehormoonid play a crucial role in growth and development, particularly in fetal development and childhood. They are vital for normal brain development and maturation. In adults, they regulate basal metabolic rate, influencing how the body uses energy from food. They affect heart rate, body temperature, digestion, and muscle function. Imbalances in kilpnäärmehormoonid can lead to various health conditions, such as hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid).