Despite being the size of a pea, the pituitary truly is ‘master gland’

ROBERT Wadlow was born in 1918 weighing in at an unremarkable 8.7lb (3.85kg).

His parents were not unusual in size or shape and, to all intents and purposes, there was no suggestion that their child would be any different.

However, by the age of five, Wadlow was already 5ft 4in and wearing clothes made for teenagers.

This inexorable rate of growth continued until he reached the eventual height of 8ft 11in, making him officially the tallest man that has ever lived.

Wadlow did not reach this height without a bit of help, though. He had a condition known as gigantism or, more specifically, pituitary gigantism.

As a result, the hormone that usually promotes growth within our bodies (imaginatively named the growth hormone) was produced at uncontrolled levels that meant even when he died (sadly, when he was just 22) Wadlow was apparently still growing.

The pituitary gland is one of a number of endocrine glands throughout our body. An endocrine gland is a group of cells that secrete hormones into the bloodstream.

Hormones are chemicals that travel throughout our bloodstream, acting on particular cells to stimulate certain actions and endocrine is the word used to describe anything to do with hormones.

Thus growth hormone promotes growth, thyroid hormones help cells metabolise and produce energy, oestrogen is a hormone that regulates the reproductive system and so on. In total, there are more than 50 types of hormone whizzing round our bloodstream, each one heading to different parts of the body.

The secretion of hormones into the bloodstream is often in response to signals from all sorts of sources that give information on whether there is need for more or less of that hormone, so the whole system is constantly in search of that delicate balance. This balance is known as homeostasis and is a coveted prize.

It is perhaps inevitable that such a complex system is subject to a few hiccups. In Wadlow’s case, it was more than just a hiccup.

The pituitary gland is a pea-sized protuberance at the front of the brain, sitting on a small ledge of the skull just behind the eyes.

In Wadlow’s case, a benign growth, called an adenoma, began to develop on his pituitary gland during his growing years.

This resulted in the secretion of too much growth hormone, causing gigantism. In people to whom it happens in later life, it causes the condition known as acromegaly (acro — extremities, megaly — great).

The pituitary gland doesn’t just stop at producing growth hormone. In fact, it produces around eight other hormones including thyroid stimulating hormone, prolactin (involved in the production of breast milk), adrenocorticotrophic hormone, follicle-stimulating hormone and luteinising hormone.

An issue with the gland, such as an adenoma or trauma to the brain in the form of a head injury or even radiotherapy, can therefore have knock-on effects on all sorts of processes within the body.

Its breadth of influence has given rise to it being referred to as the “master gland”.

Let’s take the adrenocorticotrophic hormone as an example. While you may not have heard of this hormone, there’s a good chance you might have heard of cortisol.

Cortisol is a hormone that is produced by a gland called the adrenal gland (so named because it sits next to the kidney, itself referred to as the renal organ after its Latin origin).

The adrenocorticotrophic hormone is produced by the pituitary gland to stimulate the release of cortisol from the adrenals.

Once released, cortisol (a type of steroid hormone) gets to work on all sorts of processes vital to life. These include regulating blood pressure and the immune system, helping to balance the effect of insulin (a hormone produced by the pancreas) to control blood sugar levels and helping the body respond to stress.

Too much cortisol can give rise to weight gain, a round facial appearance (it has been suggested that Henry VIII might have had too much), increased fat around the base of the neck and between the shoulders (often referred to as a buffalo hump), easy bruising and weak muscles.

It also puts you more at risk of raised blood pressure and diabetes mellitus.

This set of symptoms was first described by Harvey Cushing in 1912, hence its current name of Cushing’s disease. This is most commonly caused by synthetic steroids taken by patients who need it to treat conditions such as asthma, colitis or rheumatic conditions.

However, it can also occur as a result of a growth in the pituitary gland that causes it to pump out too much adrenocorticotrophic hormone.

Conversely, too little adrenocorticotrophic hormone (due to pressure from a non-functioning adenoma, for example) can lead to low cortisol levels, which can be life-threatening and requires the replacement of steroid hormones.

The condition known as Addison’s disease occurs when the adrenals themselves stop producing steroid hormones, including cortisol, but this is not directly related to the pituitary.

Either way, considering the complex balance of homeostasis which the body is constantly working towards, trying to do this manually with synthetic hormone is challenging and requires a lot of specialist input.

Diabetes mellitus is hopefully well known to all as an issue with the balance of sugar within the body.

Hormones are integral to that in the same way they are integral to the condition known as diabetes insipidus.

Diabetes means “to siphon” in Greek, mellitus means “sweet” and insipidus means “tasteless”. Diabetes insipidus results in excessive peeing, with the knock-on effect of increased thirst.

While the mellitus form can also result in this, the processes behind it are very different.

Mellitus draws water out into the urine in an attempt to get rid of the excess sugar, while insipidus occurs when there is too little of the anti-diuretic hormone. This is normally produced by the pituitary gland. A diuretic is a chemical that makes you pee so it follows that the anti-diuretic hormone does the opposite and causes you to retain water. This has other effects too, including increasing blood pressure.

If the pituitary is not doing its job, the floodgates open. In severe cases, a sufferer can pee up to 20 litres a day but fortunately this is rare, with only around one in 25,000 people affected.

I’ve not touched upon the various other hormones involved with the pituitary but hopefully this gives you an idea of its fairly extensive and vital role within the body. For something weighing less than a gram, that’s pretty impressive.

And while an issue with the pituitary can present with symptoms pretty much anywhere, a growth over the gland itself can also put pressure on the nearby optic nerves which cross as they both leave their respective eyes.

Pressure here can produce a unique visual loss known as a bitemporal hemianopia which is essentially a complicated way of describing visual loss in the outer half of each eye. Should this happen, look to the pituitary gland.

With all of that said, its name still derives from what people thought was its original function, namely the production of phlegm.

Pituita is a Latin term for phlegm and this was supposedly a widely held believe until the 17th century, after which it became clear that the pituitary gland was much, much more.

Armed with this knowledge, it’s unlikely we’ll see a credible challenge to Robert Wadlow’s record any time soon.