Mechanism of action of steroid hormones

The mechanism of action of steroid hormones - gene expression theory.

The molecular weight of steroid hormones is small and fat-soluble. It can be transported into target cells by diffusion or carrier. After entering the cells, the hormones bind to receptors in the cytoplasm to form a hormone-receptor complex. With the participation of appropriate temperature and Ca2+, the ability to undergo an all-transformation through the nuclear membrane occurs.

After entering the nucleus, the hormone binds to the receptor in the nucleus to form a complex. This complex binds to a non-histone specific site of chromatin, initiates or inhibits the DNA transcription process at that site, thereby promoting or inhibiting the formation of mRNA, and inducing or reducing the synthesis of certain proteins (mainly enzymes), Achieve its biological effects. A hormone molecule can generate thousands of protein molecules to achieve hormone amplification.

When hormones in muscle activity respond to muscle activity, various hormones, especially the hormonal levels of mobilizing energy supply, change to varying degrees, affecting the body's metabolic level and the functional level of each organ. Certain hormone levels were measured during exercise and during post-exercise recovery, and compared to the resting value, the change was called the hormonal response to exercise. The response and adaptation of major hormones to exercise are shown in Table 12-2.
Viru divides hormones into three types according to the speed of changes in various plasma hormones during exercise.

Fast-acting hormones immediately after the start of exercise, the hormones in plasma are significantly elevated and peak in a short period of time, such as adrenaline, norepinephrine, cortisol and adrenocorticotropic hormone.

After the start of the intermediate reaction hormone movement, the hormones in the plasma slowly and steadily rise and peak in a few minutes, such as aldosterone, thyroxine and vasopressin.

The hormones in the plasma do not change immediately after the start of the slow-reaction hormone movement. When the exercise reaches 30-40 minutes, it rises slowly and reaches a peak at a later time, such as growth hormone, glucagon, and calcium reduction. And insulin.