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5 wrz 2023 · Tests measuring free T4 – either a free T4 (FT4) or free T4 index (FTI) – more accurately reflect how the thyroid gland is functioning when checked with a TSH. The finding of an elevated TSH and low FT4 or FTI indicates primary hypothyroidism due to disease in the thyroid gland.
15 maj 2024 · This thyroid test analyzer will help you understand your TSH, T3, T4, and other thyroid function test results. Select a test and enter your lab value to learn more.
The amount of T4 and T3 secreted by your thyroid gland is regulated by the pituitary gland, which lies underneath your brain. The pituitary senses the level of thyroid hormones in your bloodstream, just as the thermostat in your living room senses the temperature.
28 maj 2024 · Thyroid-stimulating hormone (TSH): High TSH levels are a sign of an underactive thyroid (hypothyroidism). They show that the pituitary gland is trying to stimulate the thyroid gland to produce thyroid hormones.
All reactions necessary for the formation and release of T3 and T4 are controlled by thyroid-stimulating hormone (TSH), which is secreted by pituitary thyrotropic cells. TSH secretion is controlled by a negative feedback mechanism in the pituitary: Increased levels of free T4 and T3 inhibit TSH synthesis and secretion, whereas decreased levels ...
5 cze 2023 · TRH is a tropic hormone, meaning that it indirectly affects cells by stimulating other endocrine glands first. It binds to the TRH receptors on the anterior pituitary gland, causing a signal cascade mediated by a G-protein coupled receptor. Activation of Gq protein leads to the activation of phosphoinositide-specific phospholipase C (PLC).
6 gru 2023 · Secretion of the thyroid hormones T4 (thyroxine) and T3 (triiodothyronine) is regulated by pituitary thyroid-stimulating hormone (TSH) (figure 1 and figure 2). TSH secretion, in turn, is controlled through negative feedback by thyroid hormones (see "Thyroid hormone synthesis and physiology").