Hormones are the chemical messengers in the animal body.
Their function is vital for the normal body physiology.
The deficiency or hypersecretion can lead to hormonal disorders in case of malfunction.
So, their synthesis and secretion is tightly regulated by the brain.
How hormones work
Hormones work by 2 distinct methods like
1. Hormonal secretion and inhibition
2. Hormonal action on the nuclear receptors to bring the effect.
First method related to production and release of hormones. The second method relates to hormonal action on the nucleus to bring out the effect.
Hormonal secretion and inhibition:
This happens in two steps.
- Signal by the simulator for Synthesis
- Inhibition of the secretion of the simulator.
Most hormones are secreted by stimulation form anterior pituitary hormones.
These hormones are synthesized and then secreted into the blood. When the blood levels reach a specific point, they are inhibited by on feedback signal.
The signal for synthesis: Hormonal synthesis is done by endocrine glands in the body. However, hormonal synthesis is initiated by a signaling pathway. This stimulated the glands to synthesize the hormone.
For example, the thyroid stimulating hormone (TSH) regulates secretion of thyroid hormones. TSH is secreted by the anterior pituitary gland. This TSH stimulated on the thyroid gland to synthesize thyroid hormones. The thyroid hormones like thyroxine (T4) and triiodothyronine (T3) are formed as a result. These two hormones are then carried by the blood to all the tissues of the body.
Inhibition of stimulation/secretion: This is inhibition of TSH secretion. When the blood levels of T3 and T4 are high, a feedback mechanism is initiated. This negative feedback inhibition signal stops the secretion of TSH. This hinders the further formation of thyroid hormone.
So, the secretion of TSH directly controls the formation and release of T3 and T4 hormones.
Hormonal action on the nuclear receptors:
This step is the actual mechanism by which hormones action is seen at the cellular level. Hormones enter the cell membrane and the nucleus. There, they act on the nuclear receptor. This leads to conformational changes in the genes. This brings the protein synthesis at the nucleus and thereby the hormonal effect.