The Hormones Secreted by the Pituitary Gland

Before going on to consider the names of the pituitary hormones, it is worth repeating that the purpose of this site is to examine those amazing things that happen in the hormonal system that astound even the world of science, and to consider more closely the creative art of God. For this reason, it is better to concentrate on how this system functions, rather than on the names of the hormones. The complex Greek and Latin terms used in medicine and biology are a deterrent for many people. And sometimes these Greek and Latin terms just make the operations of a very simple mechanism more difficult to understand (or to prevent us from appreciating the wonder that occurs in an amazing process). The majority of experts in medicine or biology may not apprehend the wonders that are before them owing to the magic of these words. For example, they know in great detail how the pituitary gland is structured and how it functions, but they never think about the source of the intelligent consciousness that this tiny piece of flesh demonstrates. For this reason, we repeat that it is not necessary to daunt readers unacquainted with medical literature by devoting space to definitions of these terms. We will only briefly mention the names of the hormones and in the following pages we will examine the great wonders of which they are the vehicles.

The pituitary gland is composed of two parts: the anterior and the posterior glands. Each part secretes different hormones.

The Anterior Pituitary Gland

Commands come continually to all parts of the body from the pituitary gland. By means of these commands, a considerable number of the perfect operations in the body occur.

The anterior pituitary gland secretes six different hormones, whose functions have been determined. Some of these hormones that act on other hormonal glands are called "tropic hormones." They are designed to direct the hormonal system. In the following pages we will examine the functions of the tropic hormones together with the structure and functions of the hormonal glands that they affect. Another group of these hormones stimulate the tissues of the body. The names of these hormones are as follows:

Hormones which stimulate other endocrine (hormone) glands (Tropic Hormones):

1. Thyroid-stimulating hormone (TSH)

2. Adrenal gland stimulating hormone (adrenocorticotropic hormone - ACTH)

3. Follicle-stimulating hormone (FSH)

4. Luteinizing hormone (LH)

Hormones that act on body tissues (Non-tropic hormones)

5. Growth hormone (GH)

6. Prolactin hormone (PRL)

The Posterior Pituitary Gland

The posterior section of the pituitary gland is the location where the hormones produced by the hypothalamus are stored. Under the right circumstances, these hormones are secreted by a command from the hypothalamus. These hormones are:

1. Vasopressin (antidiuretic hormone)

2. Oxytocin

The Miracle of Growth: The Growth Hormone

A one-year old baby is about twice as heavy and 50% as long as on the day he was born. In one year, he gains weight at an amazing rate. He also grows longer, and his body grows in proportion. What causes a newly born baby who weighs three kilograms and is 50 centimeters long at birth to become a fully grown adult weighing 80 kilograms and measuring 1.80 meters twenty years later?

The answer to this question is hidden in the growth hormone found in an amazing molecule secreted by the pituitary gland.

In order for a baby to become an adult, he must grow. The growing process happens in two different ways. Some cells increase their bulk; other cells divide and multiply. What directs and ensures these two processes is the growth hormone.

The growth hormone is secreted from the pituitary gland and affects all of the cells of the body. Every cell knows the meaning of the message sent to it from the pituitary gland. In compliance with this message, it grows or multiplies.

For example, the heart of a newly born baby is about one-sixteenth the size of an adult heart, yet the total number of cells in the baby's heart is the same as that in the adult heart. As the body develops, the growth hormone affects the heart cells individually. Every cell develops according to the command given to it by the growth hormone. As a result, the heart grows and becomes an adult heart.

The growth hormone works like an expert sculptor. Over a period of time, it turns a 50-cm. long baby into fully grown adult of 180 cm.

The multiplication of the nerve cells stops when the baby is six months old and still lives inside the mother's womb. From this time until birth and from birth to adulthood, the number of nerve cells remains constant. The growth hormone commands the nerve cells to increase in size. When the period of growth of the nervous system has come to an end, it has reached its final form.

In the picture at the bottom we see an adult heart. While still in the embryonic stage, a baby's heart develops under the supervision of the growth hormone. In the picture at the top, we see the developing heart that appears as a red nodule.

Other cells in the body (for example, muscle and bone cells) divide and multiply throughout their period of development. Again, it is the growth hormone that informs the cells how much they must divide.

In the light of these circumstances we must ask this question:

How is it that the pituitary gland knows the correct formula according to which the cells must divide and grow? It is amazing that this piece of flesh, the size of a chickpea, controls all the cells of the body and causes them to grow by dividing or increasing their bulk. Another question that must be asked is: who charged this piece of flesh with this function? Why do these cells throughout their lifetime send messages commanding other cells to divide?

Here again we see the flawless excellence of God's creation. Cells located in one small area ensure the orderly division of trillions of other cells. However, it is impossible for these cells to observe the human body from outside to determine how much the body must grow and at which stage it must stop growing. These unconscious cells, in the darkness of the body, without even knowing what they are doing, produce the growth hormone (and cease producing it) when necessary. A perfect system has been created that controls every stage of growth and secretion of this hormone.

Obeying the growth hormone, our cells construct our faces with perfect balance and symmetry. The cells meticulously obey the command they receive and grow in proportion to one another. Otherwise, the symmetry in the human face would not be possible; if the nose grew too large, the cheekbones may not develop. Or, if the eye grew but the eye sockets did not, the eye would not be able to perform its function.

It is another wonder that the growth hormones command some cells to increase in size and others to multiply by cell division because the hormones that reach each kind of cell are identical to each other. How the cell that receives the command must react is written in its genetic code. The growth hormone issues the command to grow; how that growth will occur is recorded in the cell. This shows the power and magnificence of creation at every point in the development of the human body.

Yet another very important point is the fact that the growth hormone affects most body cells. If some cells obeyed the growth hormones and others did not, the result would be a disaster. For example, if the heart cells obeyed the commands of the growth hormone but the cells in the rib cage refused to multiply and grow, what would happen? The growing heart would be squeezed in the undersized chest cavity and die.

The growth hormone ensures that all of the organs in the body grow proportionately to one another. For example, development of the organs in the abdominal cavity and of the chest cavity is proportionate. If the growth of the chest cavity stopped and the heart continued to develop, the rib cage would crush the heart and cause death.

Or if the bone of the nose grew but the skin on it stopped growing, the bone of the nose would tear the skin and become exposed. The harmonious growth of muscles, bones, skin and other organs is ensured by the obedience of each individual cell to the growth hormone.

The growth hormone also gives the command for the development of cartilage at the ends of the bones.1 This cartilage is like the unformed shape of a newly born baby; if it does not grow, the baby cannot grow. The cells in this area cause the bone to grow lengthwise but how do they know that the bone must grow in this way? If this bone grew sideways, the leg would not lengthen; it could even rip the skin and be exposed. But everything is planned and this plan is written in the nucleus of every cell.

Another astonishing fact about the growth hormone is when it is secreted and how much. The growth hormones are secreted in exactly the right amount and at the time when the period of growth is most intense. This is very important because, if the amount of hormone secreted were more or less than what is needed, the result would be quite undesirable. If too little hormone is secreted, dwarfism occurs, and if too much is secreted, gigantism is the result.2

So, for this reason a very special system for regulating the amount of this hormone secreted in the body has been created. The amount of this hormone secreted is determined by the hypothalamus, which is recognized as the director of the pituitary gland. When it is time for the growth hormone to be secreted, it sends the "growth hormone-releasing hormone" (GHRH) to the pituitary gland. And when too much growth hormone has been released into the blood, the hypothalamus sends a message (the somatostatin hormone) to the pituitary gland and slows down the secretion of the growth hormone.3

Every bone cell in the body knows where it will be, what shape it will have, and how large it will grow. They obey without error the commands they receive from the growth hormone. This communication among its cells allows the body to grow in proportion.

Yet how do the cells that compose the hypothalamus know how much growth hormone there should be in the blood? How do they measure the amount of growth hormone in the blood and made a decision based on this amount? In order to explain just how great a wonder this is, let us consider an example:

Let us imagine that we have used a special device and reduced a person to several millionths of his original size, that is, to the size of a human cell. We have put him in a special capsule beside one of the cells in the region of the hypothalamus.

The job of this person is to count the number of growth hormone molecules in the capillaries passing in front of him. He determines if there is a reduction or an increase in the number of these molecules. It is well known that there are thousands of different materials contained in the blood. It is impossible for a human being (if he is not an expert in the field) to know from the molecular structure if something in front of him is a growth hormone or something else. But the person we placed in the hypothalamus must recognize with certainty the growth hormones among millions of other molecules. Moreover, he must check the amount of the hormone at all times.

How can the unconscious hypothalamus accomplish this task, which seems very difficult even for a human being? How does it measure at every moment the amount of growth hormone in the blood? How does it distinguish the growth hormone from other molecules? These cells do not have eyes to recognize molecules, or brains to evaluate a situation. But they put into effect the commands given to them in perfect a system that God has created.

If a little too much or too little growth hormone is secreted, the results are dynamic. If too little is secreted, dwarfism occurs; if too much, gigantism is the result. For this reason, God has created a special system to regulate the amount of growth hormone secreted.

The growth hormone is not only secreted in the developmental period but also continues in adulthood. Under these circumstances you would expect that people would continue to grow and become gigantic. But this does not occur.4 When a person reaches a particular size, his cells do not continue to divide and grow. Scientists still do not know why this happens. It is known that thanks to a very special system, cells are programmed not to divide and grow any more after a certain time. Given this situation, a person should think about the Power that created this perfect program. This shows us another wonder of God's creation.

It is not very difficult to understand how important it is that trillions of cells stop dividing and growing together at the correct time. If some of these cells did not stop dividing as others did, the result would be terrible. For example, if the eye cells continued to divide and multiply after the other cell groups have ceased to do so, the eye would be squeezed in its socket and burst.

After speaking about trillions of cells suddenly stopping their activities, there is something else worth remembering. Cancer is a disease that we have been fighting for decades and still have not conquered; it is caused by one single cell continuing to divide out of control. This example permits us to better understand the delicate balance that exists in the body.

In adulthood, the growth hormone continues to have an influence on a few special cells and stimulates these cells to divide and multiply. This is another wonder of creation that serves a special purpose. This cell division no longer causes the body to grow, but serves to repair and regenerate the body. For example, skin cells and red blood cells continue to divide causing our bodies to gain 200 million new cells every minute.5 These cells replace old and damaged cells. By this means, the total number of cells remains constant.

The growth hormone has a special design by which it brings several factors into use to ensure cell division and growth.

It is not possible for us to count the number of growth hormone molecules in our body's capillary vessels or to easily determine a rise or fall in that number. But the cells that make up the hypothalamus select the growth hormone from among the thousands of different materials in the blood and make the required adjustments.

For cell division and growth to occur, it is first necessary that the cells increase in size, which is possible only through an increase in their amount of protein. So, the growth hormone has a special function in accelerating the production of protein in the cell.

In the above photographs, we see a woman at 16, 33 and 52 years of age who has a condition caused by excessive secretion of growth hormone during adulthood. This condition is characterized by disproportionate growth in the jaw, hands and nose.

It is known that protein production occurs as the result of a complex process. Scientists have been able to understand only some of the superficial elements in this process after long years of research. In order to produce one molecule to accelerate the operation of this system, it is necessary to know all aspects of it. The fact that the growth hormone has a design that enables it to speed up the production of protein is a proof that the system that produces protein and the growth hormone are created by God to act in harmony with each other and perform their functions according to His command.

The growth hormone not only ensures the acceleration of the synthesis of protein, but also ensures that the requisite amount of raw material enters the cells for this purpose. The main material needed for the synthesis of protein is amino acids, the building blocks of protein. As if they were aware of this information, the growth hormone stimulates the cell membrane so that it can receive more amino acids.

In order to speed up the synthesis of protein, the metabolism of the cell must also be accelerated and, to this end, the growth hormone cooperates with other hormones. The thyroid hormone secreted during the period of growth accelerates the metabolic activities of the cells.

In the above picture of a growth hormone. It is too small to be seen with the naked eye but it acts within the body with a high level of consciousness, intelligence and sense of responsibility. It is a wonder how it is able to make a perfectly formed human being. But the One Who actually creates this wonder is God, the Lord of all the worlds.

In order for all this to happen, one more very important thing is needed: energy. Even if all the systems we have mentioned so far were perfect, they would be of no use without a source of energy. Without energy, the growth process could not occur. But the human body has been so perfectly planned that this need too has been provided for. In addition to all these intricate functions, the growth hormone performs one more very important duty. It ensures the release of fat molecules to mix with the blood. In this way, each molecule will serve as a source of fuel fulfilling the cell's energy needs.

When the growth hormone reaches the cell, it attaches itself to the appropriate receptor on the membrane. When the receptor is stimulated, the growth hormone begins to perform its function.

When reading about the activities of the growth hormone in the body, it is important to recall that what accomplishes this is a lifeless, unconscious molecule formed by the combination of a few atoms that have no hands, eyes, or brain. It is remarkable that a lifeless bit of matter can know when and where to go in the body, and when, how and by what means to stimulate it. Unconscious atoms cannot write messages and send them to one another, but this wonderful event happens when some molecules interact with each other. They immediately know what they must do and then do it. For example, when some molecules interact with the growth hormone, they immediately begin to divide. Others decide to take more amino acids. And for this it is only necessary to respond to the growth hormone. How can such a conscious and organized activity continue without interruption in the body?

To claim that all these wonderful balances came to be in the course of time by the operation of chance flies in the face of scientific fact and logic. This is because only one deficiency could destroy the whole system. In order for a living thing to survive, its whole system and all its organs must come to be at the same time. Everything reviewed so far about the growth hormone and these delicate interrelated balances demonstrates the fact that human beings were created perfectly as a complete organism. Concerning the excellence of creation, God says in the Qur'an:

He is God-the Creator, the Maker, the Giver of Form. To Him belong the Most Beautiful Names. Everything in the heavens and Earth glorifies Him. He is the Almighty, the All-Wise. (Qur'an, 59: 24)

2 Arthur C. Guyton, John E. Hall, Textbook of Medical Physiology, 10. Edition, W.B. Saunders, p. 581.
3 Biological Science: A Molecular Approach, BSCS Blue Version, 6. Edition, Colorado 1990, p. 521
4 The Incredible Machine, Washington D. C. National Geographic Society, 1986, p. 226
5 The Incredible Machine, pp. 222, 225