[Lotus]

The mechanism of secretion of hormones, their delivery to target cells and purification of metabolic crucial for normal functioning of the endocrine system. Method for production of steroid hormones studied enough, but it is known that these hormones accumulate in those tissues where they are produced.

Thyroid hormones, catecholamines and peptide hormones are packaged into granules are formed from the endoplasmic reticulum. When you combine these vesicles with the cell membrane leads to the release of hormones in the blood.

In many cases, some of the circulating hormones associated with plasma proteins. However, generally speaking, the hormones in physiological concentrations in the dissolved state, and there is no data to indicate any mandatory role of such proteins in the hormonal effects. The reasons for their existence, are unknown. Typically, active apparently free, but are not bound to plasma proteins share of hormone binding in blood plasma, obviously, limits, rather than increases the likelihood of the hormone on target cells.

In some cases, proteins that bind the hormone with high affinity bulk plasma hormones. Examples include thyroxine binding globulin (TBG) and thyroxine prealbumin (TSPA), which binds thyroid hormones, as well as corticosteroid binding globulin (GAC or transkortin), which binds cortisol.

Cholesterol can also be viewed as a hormone, because it is synthesized in the liver, passes from the blood (due, mainly, low-density lipoprotein (LDL)) in peripheral tissues and inhibits its biosynthesis. It may represent an exception to the above generalization: it is completely insoluble steroid and LDL to act as a carrier hormone.

Source: collegiate