Early on, scientists had a vague idea that there are certain messenger substances in the body that served as informational agents for the organs. However, it was a long way to the discovery of the hormones. The two English physiologists Ernest Henry Starling and William Maddock Bayliss succeeded in 1902 a significant step in hormone research. They were able to show that the pancreas was still functioning after severing all the nerves leading to it.
The reason: It secretes digestive substances as soon as the stomach contents enter the intestine. The two scientists discovered in this way a humoral messenger substance, which they called secretin.
Discovery of other hormones
In 1905 Starling proposes the name "hormone" (hormao (Greek) = I urge) to designate all substances that enter the blood through special glands and stimulate other organs to activity. The discovery of other hormones, including 1905 gastrin, 1921 insulin and 1972 somatostatin showed that the Englishman had made a real breakthrough in hormone research.
The first hormone to be isolated and its structure determined was adrenaline. As early as 1901, the Japanese-American chemist Jokichi Takamine (1854-1922) was able to gain from the adrenal gland. A short time later, this substance was recognized as a hormone according to the findings of Starling and Bayliss.
What are hormones?
Without hormones in the human body nothing works, because hormones transmit important information so that cells and organs can function properly. Hormones are therefore endogenous substances that achieve a precisely coordinated effect in minimal concentration. They are in certain glandular cells of different organs such. B. the pancreas produced. From their place of education, they are released into the bloodstream and pass through the bloodstream into certain organs of success, where they develop their specific effect.
Hormones or hormone-like substances that are not formed in special glands but directly in the tissue are called tissue hormones.
Which "endocrine glands" produce hormones?
- Hypothalamus, pituitary gland
- Gastrointestinal tract
- Adrenal cortex, adrenal medulla
- adipose tissue
In order to be effective in the cells of the organs of success, they must bind to hormone receptors, which are special structures on the surface or within the cell. The receptor and the hormone fit together like a key and a lock, which is why this recognition system is also called the key-lock principle. If the hormone unlocks the receptor lock with its key, it triggers the metabolic processes in the cell, eg. B. a chemical reaction within the cell.