An interesting question to ask is: How are these hormone secretions controlled? Actually, the better question to ask is: who-controls these glands that secrete the hormones? Till the 1930s, it was widely assumed that there was no master control for these hormonal glands and that somehow the glands ‘knew’ what they were doing and responded to various events correctly. With time, scientists determined that the different glands were not autonomous but were under the control of something else.
It was observed that a gland (called the pituitary) located just below the brain seemed to affect the output of other glands. Like many scientific discoveries this was demonstrated negatively by studying patients with damaged pituitary glands. In such cases, the hormone secretion through the rest of the body became disordered.
Careful scientific experiments showed that a peripheral gland releases its hormone only if the pituitary first releases a hor-mone that tells the gland to do its job. The pituitary contains a whole array of hormones that run the hormonal show in the body. The obvious conclusion was that the pituitary was the real master gland of the body. The popular press4 at that time, helped to disseminate this view far and wide.
By the 1950s many scientists were discovering that the pituitary was not the real master gland at all. The simplest experiment involved removing the pituitary from an animal and putting it in a bowl filled with pituitary nutritive material. Observations showed that the pituitary behaved abnormally.
The sceptics argued that the pituitary was traumatized and taking anything out of the body and putting it in a bowl will mean that it will not secrete a lot of hormones. Interestingly, while levels of some hormones secreted were quite low, the others were secreted at extremely high levels. It turned out that the pituitary was acting erratically because it really was clueless about the hormonal plan and it was not receiving any orders from its boss. The boss turns out to be the brain.
Experiments clearly showed the brain to be in charge of the pituitary. If a portion of the brain near the pituitary is destroyed, the pituitary starts to act erratically. It was clear that the brain must have some mechanism that it uses to communicate with the pituitary. As the pituitary is located so close to the brain, by all logic, there should be nerve projections from the brain to the pituitary (similar to the nerve projections going to the different parts of the body like the heart) and for the brain to release neurotransmitters to communicate with the pituitary.
Unfortunately, no one could find these projections. One of the pioneers in this field, the physiologist Geoffrey Harris proposed that the brain was also a hormonal gland and that it released hormones into the bloodstream like the other glands.
These hormones travelled through the bloodstream and reached the pituitary where they directed its actions. A lot of scientists at that time thought that these ideas were outlandish. Two scientists, Roger Guillemin and Andrew Schally, began looking for these brain hormones. What unfolded was a drama worthy of a movie (well, if not a full movie at least a mini-serial on TV)!