The hormones found in the body are a group of compounds that have a common theme and that is they act as a control mechanism for the vast number of processes that occur within the human body every day.
They are part of numerous homeostatic (self-balancing) mechanisms, all of which are designed to ensure that these processes function optimally and therefore from an evolutionary standpoint offer the best chances of survival. Most of these hormones act via a feedback mechanism and the best way of illustrating this is to use an example. And what better example than control of blood glucose.
Insulin is the hormone that is produced by the beta cells in the pancreas and is released from the cells in response to a rise in blood glucose. It is absolutely essential that our blood glucose is maintained within fairly strict parameters, namely 4.4 – 6.2 mmol/l. So, when we ingest some carbohydrate this is broken down in the gut and is absorbed into the body as glucose. A rise blood glucose will promote insulin secretion from the pancreas and the function of insulin is to push the glucose into the individual cells via the insulin receptor for immediate utilization. If it cannot be utilised then it is converted to fat and stored as such and this is the bodies way of not wasting a potential energy substrate.
When the blood glucose begins to fall the insulin secretion from the pancreas is shut off and glucose levels return to a point within that narrow band. If the blood glucose begins to fall below that lower limit of normal then a second hormone called glucagon, produced by the liver is released and its function is to promote a process called gluconeogenesis which is the production of glucose from non-carbohydrate sources, namely amino acids and glycerol.
This is of vital importance because the central nervous system i.e. the brain and spinal cord have an obligatory requirement for glucose. It is unable to use the secondary substrate that the rest of the cells in the body are able to use, namely fatty acids. So that is a perfect example of how hormones are designed to regulate the numerous complex systems and processes within our body.
Other examples of hormones that are produced routinely are adrenalin, cortisol, and human growth hormone (HGH). These are worth mentioning because in fact they are produced in response to a perceived necessity by the individual to utilise energy rapidly and from an evolutionary perspective this of course was necessary when food was scarce and the individual needed to go out and hunt and gather for some more.
Typically, this was first thing in the morning and this explains why once again from an evolutionary perspective, these hormones tend to be released at this time of day and importantly act in exactly the same way when we introduce intermittent fasting as a way of countering insulin resistance and therefore obesity. Many people think that if they don’t have breakfast first thing in the morning then their bodies will cease to function. These hormones act to ensure that quite the opposite happens and in fact the body is both physically and mentally much more alert in the fasted state.