Quite early on, scientists had a vague idea that there were certain messenger substances in the body that served as mediators of information to the organs. However, it was a long way to the discovery of hormones. In 1902, the two English physiologists Ernest Henry Starling and William Maddock Bayliss achieved a significant step in hormone research. They were able to show that the pancreas still functioned after all the nerves leading to it had been severed.
The reason: it secretes digestive substances as soon as the stomach contents enter the intestine. In this way, the two scientists discovered a humoral messenger substance they called secretin.
Discovery of other hormones
In 1905, Starling proposed the name “hormone” ( hormao (Greek) = I drive ) to describe all substances that enter the blood through special glands and stimulate other organs to activity. The discovery of other hormones, including gastrin in 1905, insulin in 1921 and somatostatin in 1972, showed that the English 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 extract it 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, nothing really works in the human body, because hormones transmit important information so that cells and organs can function properly. Accordingly, hormones are substances produced naturally in the body that have a precisely coordinated effect in minimal concentrations. They are produced in certain glandular cells of different organs, such as the pancreas. From their site of formation, they are released into the bloodstream and travel through the circulation to specific organs of success, where they exert 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
-
Gonads
-
Kidneys
-
Thyroid gland
-
Liver
-
Parathyroid gland
-
Gastrointestinal tract
-
Adrenal cortex, adrenal medulla
-
Adipose tissue
-
Pancreas
-
etc.
Key-lock principle
To exert their effect in the cells of the organs of success must bind to hormone receptors, which are special structures on the surface or inside the cell. In this process, 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. Once the hormone has unlocked the receptor lock with its key, it triggers the metabolic processes in the cell, such as a chemical reaction within the cell.
