Regulation of Thyroid Hormone.ppt for nursesx

This is useful for nursing students.

1. Regulation of Thyroid Hormone Mr Yogendra Mehta Lecturer, HOD(AHD) BRNC

2. Hormones It produces two principle hormones Thyroxine (T4 ) Triiodothyronine (T3) Also secrete calcitonin(responsible for Ca homeostasis ) Cells in the following tissues, glands, organs and body systems can convert T4 to T3 through De- Iodinization: Liver Kidneys Muscles Thyroid. Pituitary gland. Brown adipose (fat) tissue (This type of fat produces heat to help maintain your body temperature in cold conditions). Central nervous system

3. Biosynthesis of thyroid hormones Iodine is essential for synthesis of thyroid hormones . Steps of synthesis Uptake of iodine: Formation of active iodine Thyroglobulin and synthesis of T3 and T4

4. Regulation of thyroid hormone

5. Functions

6. Regulation of Thyroid Hormone Iodine: - When iodine intake falls below about 100 mcg/day TSH secretion increases. TSH increases thyroidal iodine uptake from the blood and produce thyroid hormone . Dietary iodine is absorbed via the small intestine and, in the thyroid, incorporated into thyroglobulin , ultimately forming the pro-hormones, thyroxine (T4) and triiodothyronine (T3). Thyroglobulin ( Tg ) is a glycoprotein homodimer produced predominantly by the thryroid gland. It acts as a substrate for the synthesis of thyroxine and triiodothyronine as well as the storage of the inactive forms of thyroid hormone and iodine.

7. Regulation of Thyroid Hormone In Euthyroid , Iodine has two effects at two different times. The most rapid (hours to days) effect, at pharmacologic doses of KI,  decreases thyroglobulin proteolysis , thereby decreasing thyroid hormone secretion. Wolff- Chaikoff effect : The proposed mechanism is that  iodopeptide (s) are formed that temporarily inhibit thyroid peroxidase (TPO) mRNA and protein synthesis and, therefore, thyroglobulin iodinations .

8. Normal Value Thyroglobulin :- 3 to 40 nanograms per milliliter TPO( Anti-thyroid peroxidase) antibodies in the blood may mean you have thyroid disease due to an immune system condition called Hashimoto's disease.