The Truth About Hormones

Vivienne Parry

• Publisher: Atlantic Books
• Year: 2014
• ISBN:
  9781782394907
• Topic: Medicine
• Subtopic: General Health

CONTENTS

Acknowledgements

Introduction

ONE

A BLUFFER’S GUIDE TO HORMONES

TWO

HORMONE EXPLOSIONS 1: Attraction, Sex and Babies

THREE

HORMONE EXPLOSIONS 2: The Teenage Years

FOUR

HORMONES AND THE ENVIRONMENT

FIVE

HORMONE EXPLOSIONS 3: Hormones as Tyrants

SIX

HORMONE CRASHES

SEVEN

DO HORMONES MAKE YOU FAT?

EIGHT

HORMONES AS CLOCKS

NINE

HOLDING BACK THE YEARS

TEN

THE REIGN OF HORMONES IN THE FUTURE

References

Glossary

Index

ACKNOWLEDGEMENTS

Very special thanks to the following: Professor Eric Thomas, who gave up female hormones to be a fabulous Vice Chancellor and Professor Clive Coen, a fabulous neuroendrocrinologist, who each read my manuscript and offered much helpful comment; Professor Steve Franks, reproductive endocrinologist, for lending me several huge volumes from his hormone library, as well as for his thoughtful advice and support; Professor David Purdie, master of HRT and the spoken word for his comments on the menopause chapter, Dr Jo Marsden for her help with breast cancer; and physiologist Professor Michael Rennie, who made sense of insulin and growth hormone for me and who, when I apologized for making him read his subject transcribed for toddlers, came back with the words I want engraved on my tombstone: ‘Your demotic is sufficiently racy not to be insulting.’ Only a scientist eh?

A special thank you to Tom Parkhill and the Society for Endocrinology who were unfailingly helpful in offering their contacts and knowledge and who made it possible for me to attend the International Congress of Endrocrinology 2004 in Lisbon. They also read the manuscript with good grace, despite being surrounded by hormones.

Many doctors and scientists were incredibly generous with their time: the sperm men, Professor Chris Barratt and Dr Allan Pacey, lactation specialist Professor Peter Howie, the ever patient Dr Alan Johnson of the Centre for Ecology and Hydrology, Wallingford, Professor Roger Gosden, Professor Shlomo Melmed, the sveltest obesity expert I know, Professor Steve Bloom, Professor Howard Jacobs, Blakemores, père et fille (Professor Colin and Dr Sarah), Professor Sir Iain Chalmers, Dr Margaret Rees, Sir Dr Chris Flowers, Dr John Gilbody of Wyeth, Dr John Ashby of Syngenta, Dr Mark Lythgoe, Prof Neil Gittoes and Professor John Russell, come to mind in particular but there were many more that I bored to death with a constant stream of questions. To all of you, thank you. And what would I have done without the support, contacts and gossip from staff at the Science Media Centre, MRC, Nature News Service and the Environment Agency? I was also indulged by many of the science correspondents, including Tim Radford, Nigel Hawkes and Mark Henderson as I expounded my wilder hormone theories over a glass or three; and cosseted by John Adams, a professor of geography, who runs a course on statistics for the mathematically challenged. His attempt to instil understanding of standard deviation was largely successful.

When I last wrote a book, a decade ago, I swore I wouldn’t do another one. The combination of Toby Mundy of Atlantic Books – as inspirational, enthusiastic and talented a publisher as you could hope to find – and my agent Pat Kavanagh, changed my mind. Dr Louisa Joyner edited this book and was a joy to work with, as were all the staff at Atlantic, including Jane Robertson, the copy editor whose family probably all got socks as presents because I drove Jane witless in the week before Christmas. I feel very lucky to have found them.

I owe a great deal to my family who endured me locking myself away for too long and for my patient and loving friends whom I neglected horribly while I wrote this, and for whom the excuse ‘It’s my hormones’ wore a little thin. Finally, this book is for my father. Had they known more about hormones thirty years ago, he might have been alive today, hopefully to be proud.

Vivienne Parry

Muswell Hill 2005

INTRODUCTION

Hormones rule your world. They control your growth, your weight, your metabolism, your fertility and water balance. They initiate and regulate life changes like puberty and menopause, they have a hand in the speed of ageing, whether you want sex or not (and even whether you enjoy it), and who you fall in love with. Their effects may occur in seconds and be over in a flash, or take months and last for thirty years. They control your mood and your emotions too, especially those that grip you in the most visceral way – fear, anger, love.

Whatever your age or gender, whether you are petulant, cranky, spotty, forgetful, angry or just a little out of sorts, the odds are that someone is going to tell you ‘It’s your hormones’. Irritatingly, there’s a good chance they’re right.

The word ‘hormone’ appears in the media almost every day. Challenged, people will hazard that testosterone is one, that the pill contains them and maybe that fish are changing sex because of them. This book will explain how hormones work and introduce the myriad ways that they control your life and the controversy and outrage that so often attend them.

This book isn’t a manual for those with hormone-based conditions like diabetes, thyroid disease or infertility, for whom there are already many practical guides. It is an introduction to a secret empire of stunning complexity and elegance, and will attempt to set out the truth about hormones.

Hormones are the slaves of one of the body’s two internal communication systems. The nervous system carries messages from the brain that are transmitted throughout the body by electrical stimuli. The hormone system – more properly known as the endocrine system – is much slower, and uses the blood as its medium for communication and chemicals – hormones – as its messengers. To compare the two systems is to compare a high-speed rail network with canals, or snail mail to e-mail.

Hormones are molecules with a very long history. Even the simplest of animals needed to communicate what was going on outside its body to each of its cells inside. Without some form of internal communication, how could it coordinate a response that would ensure its survival? Come to that, how could the animal function as one organism, without some means of enabling all its constituent parts to talk to each other?

Chemical messengers work by travelling to a cell with an instruction to do something. Once they reach their target, the molecules of hormone find unique docking bays, called receptors, and deliver their message. At first it was thought that hormones in ‘higher’ animals were produced solely by special ductless glands, called endocrine glands, like the thyroid or the ovaries, and that each of these glands, with its specialized hormones, worked in isolation to do a specific job. It was then realized that the glands, which also include the testicles, the pancreas and the adrenal glands on top of each kidney, worked together, with one of them, the pituitary (positioned at the base of the brain and just behind your eyes), acting as the conductor that orchestrated them all. It is now known that the master gland is actually the brain itself, specifically a part of it called the hypothalamus, from which the pituitary dangles by a little stalk, and that lots of organs act as endocrine glands – including the placenta and gut – and that many if not all tissues including fat and muscle, produce hormones. Hormones, which were once believed to number no more than a couple of dozen, are today counted in the hundreds.

When people talk about their hormones, they talk about them in the abstract, as if they were something over which they had no control. It’s true we have no say in the genes we acquire, which contain the instructions for the various elements of the endocrine system. It’s true that hormones are a bit like breathing in that they work independently of conscious thought. But in another sense we do control them: it is our actions that drive them; they are the body’s response to our conscious activities, whether it is running a marathon, falling in love or eating Christmas lunch.

Given the complexity of the endocrine system, it is perhaps not suprising that it can go wrong. Indeed, from the earliest times the conditions caused by having too little or too much of a particular hormone were remarkable enough and common enough to attract the interest of enquiring minds. These conditions included gigantism, caused by an excess of growth hormone; the growth of a big lump on the neck called a goitre, symptomatic of too little thyroid hormone; and the wasting, decline and rapid death of those with diabetes. The removal of one set of endocrine glands – the testicles – were understood to be linked to changes in body shape and function in both humans and animals. Despite this understanding the history of hormones is a recent one, with the actual word hormone being coined only a century ago, in June 1905.

The pivotal figure in the history of hormones was Charles Eduoard Brown-Séquard. British by birth, but French by upbringing, he was a world-famous neurologist of the Victorian era. In 1855, he established that the adrenal glands, which sit one atop each kidney and produce, among other hormones, the stress hormone cortisol, were essential to life. He also refined the concept of ‘internal secretion’ – the idea that organs inside the body could produce substances which travel around the body in the bloodstream and affect the function of other organs.

However, it was to be another forty years before the word hormone was coined. In 1902 William Bayliss and Ernest Starling, physiologists working at University College London, were the first to discover and name one of these mysterious ‘internal secretions’, a hormone produced in the gut called secretin. Sir William Hardy suggested using the term hormone, which means ‘to arouse or excite’, or, as some Greek scholars would have it, ‘to urge’. The first recorded use of the word was in the annual Croonian lecture to the Royal College of Physicians, given by Starling, in June 1905. Rival groups of doctors had proposed a different name – ‘harmazones’ from the Greek ‘to regulate’ – but, perhaps luckily, given that a ‘harmazone’ sounds like something you should suck for a sore throat, ‘hormone’ was preferred.

Hormones, however, were already notorious. In 1889, Brown-Séquard, now seventy-two years old, was back in France where he had taken up the distinguished position of Professor of Medicine at the Collège de France. On 1 June, he stood before the Society of Biology in Paris and announced his own rejuvenations. The elixir? The gound-up testicles, semen and blood of guinea pigs and a dog, extracted with water, filtered, diluted and injected daily. After just eight injections, Brown-Séquard said he felt less fatigued, could lift heavier weights than before and no longer needed laxatives. The effect of this announcement from such an eminent doctor was electrifying.

While Brown-Séquard’s rejuvenating fluid was greeted with scepticism in Britain, in America it had a sensational impact. The world and his wife, or rather the world and his mistress he would like to service, beat a path to his door, clamouring for his organ extracts. Within weeks, testicular extracts were being given to patients to cure everything from high blood pressure to headaches. By the following year, over 1,200 doctors were giving this ‘elixir’ to their patients and it sparked a craze for ‘oganotherapy’ – the concept of giving extracts of a particular organ to cure problems associated with the same organ. It was soon to encompass not just testicular extracts but almost every body organ – even ‘grey matter’ – suitable for treatment of nervous diseases.

The testicular extracts had no effect, because testosterone (the ‘rejuvenating’ hormone Brown-Séquard had been seeking) was not soluble in water. They were also extremely dangerous and it was likely there were many deaths caused by infection or extreme allergic reation. While their appeal gradually receded, organotherapy endured for another fifty years in various forms, including the widespread use of implanted animal testicles during the 1930s by the so-called ‘gland grafters’, such as John Brinkley in the US and Serge Voronoff in Europe.

So, from the outset, hormones were mire...

Table of contents

• Cover
• Title Page
• Copyright Page
• Contents