The effects of thyroid hormones, 3 common effects

The effects of thyroid hormones are manifested in many aspects, and it is an indispensable hormone for promoting our body's growth and development. It is especially important during infancy. If the thyroid hormone level is low, it can easily cause intellectual retardation in infants.

1. Promote growth and development

The growth-promoting effects of thyroid hormones are most evident during infancy, with the greatest impact within the first five months after birth. It mainly promotes the growth and development of bones, brain and reproductive organs. Without thyroid hormone, the pituitary GH cannot function. Moreover, when thyroid hormone is deficient, the pituitary gland's production and secretion of GH also decreases. Therefore, congenital or childhood lack of thyroid hormone causes cretinism. Cretinism patients have stagnant bone growth and are short in stature. The length ratio of the upper and lower body is abnormal, with the upper body accounting for a larger proportion than that of normal people. Due to the growth disorders of nerve cell dendrites, axons, myelin sheath and glial cells, the brain is underdeveloped and the intelligence is low. Their sexual organs cannot mature and they do not have normal reproductive function. When a newborn has hypothyroidism, he or she should be supplemented with appropriate amounts of thyroid hormone within one year of age. This is effective for the development of the central nervous system and the recovery of brain function. If it is later than this period, even if a large amount of T3 or T4 is supplemented, normal function cannot be restored and the treatment is often ineffective.

2. Impact on metabolism

1. Thermogenic effect Thyroid hormones can increase the oxygen consumption rate of most tissues and increase thermogenic effect. This thermogenic effect may be due to the fact that thyroid hormones can increase the synthesis of Na-K pumps on cell membranes and increase their activity, which is an energy-consuming process. Thyroxine increases the basal metabolic rate. 1 mg of thyroxine can increase heat production by 4000KJ. The basal metabolic rate of patients with hyperthyroidism can increase by about 35%, while the basal metabolic rate of patients with hypothyroidism can decrease by about 15%.

2. Effects on the metabolism of the three major nutrients Its effects on the metabolism of the three major nutrients are very complex. In general, under normal circumstances, thyroid hormones mainly promote protein synthesis, especially significantly increasing protein synthesis in bones, skeletal muscles, liver, etc., which is of great significance for growth and development in childhood. However, excessive secretion of thyroid hormones will cause a large amount of protein breakdown, especially skeletal muscle protein, resulting in weight loss and weakness. In terms of sugar metabolism, thyroid hormones promote the absorption of sugar by the small intestinal mucosa and the decomposition of glycogen in the liver. At the same time, it can promote the utilization of sugar by peripheral tissues. When hyperthyroidism occurs, blood sugar rises and sometimes sugar in the urine appears. In short, it accelerates the metabolism of sugar and fat, especially promotes the decomposition and oxidation process of sugar, fat and protein in many tissues, thereby increasing the body's oxygen consumption and heat production.

3. Other aspects

In addition, thyroid hormones also play an important role in the activities of some organs. It plays an important role in maintaining the excitability of the nervous system. Thyroid hormones can directly act on the myocardium, promote the release of Ca2 from the sarcoplasmic reticulum, increase myocardial contractility, and accelerate heart rate. Effect on water and electrolytes: When the thyroid function is hypothyroid, the interstitial mucin increases and can bind a large number of positive ions and water molecules. K and Na are retained in the tissue fluid and viscous edema occurs. Effects on the nervous system: When the function is hyperactive, the excitability of the central nervous system increases.