In her book Aroused: The History of Hormones and How They Control Just About Everything (W. W. Norton and Company, 2018), physician Randi Hutter Epstein offers an engaging look not only at these amazing substances but also at the history of endocrinology. Epstein shows how the development of endocrinology as a field involved both solid scientific research and pseudoscientific claims about hormones. Although our understanding of the endocrine system has progressed over the last century, much about these complicated chemical messengers remains unknown.
The book starts with a useful metaphor for understanding the endocrine system as distinct from the nervous system. The nervous system "works like an old-fashioned operator's switchboard" in that a single nerve can be followed from beginning to end, and electrical impulses that travel along that nerve cannot jump to a different nerve. But hormones, Epstein explains, can reach a distant target with "no connections needed. They are your wireless network." In humans, there are nine major glands-hypothalamus, pineal, pituitary, thyroid, parathyroids, islets of Langerhans, adrenals, ovaries, and testes-that release hormones. These substances control or influence metabolism, growth, fertility, mood, sleep, appetite, and many other aspects of life.
Schooled in the centrality of the nervous system, late 19th-century medical researchers found it hard to believe that a minute amount of hormone released from a given gland could affect a distant body part. This changed in 1903, when British physiologists William Bayliss and Ernest Starling performed a simple experiment on a dog: after removing the neural connections to the dog's stomach, they fed it food mixed with acid. As they hoped, the dog's pancreas released a substance that neutralized the acid, confirming their theory that chemicals, not nerves, controlled digestion. They named this substance "secretin," and their work has since been confirmed by modern research. Starling first used the word "hormone" in 1905 to describe these mysterious chemical substances, and the field of endocrinology was born.
As Epstein reports, during the 1920s hormones were hailed as miracle solutions to problems as varied as crime and, in men, the loss of virility with age. Louis Berman, a physician and professor at Columbia University, claimed that criminal impulses resulted from either a deficiency or an excess of one or more hormones. Berman had examined convicted criminals, but since no existing test could assess hormones in blood, Berman's "results" were more sensationalist than scientific. Eugen Steinach, a Viennese physiologist, similarly promoted an endocrine-based "cure" for the loss of virility. Despite a lack of hard evidence, Steinach believed that giving middle-aged men vasectomies would restore their virility, and many famous men-including Sigmund Freud and the poet William Butler Yeats-were "Steinached."
Endocrinology gained greater recognition as a science during the 1960s, largely because of the work of physicist Rosalyn Yalow and her colleague, Solomon Berson, an internist. Together they developed the technique of radioimmunoassay (RIA), which made it possible to determine how much of any one hormone a person had in their blood. The use of RIA quickly spread around the world, and in 1977, Yalow won the Nobel Prize (Berson had died in 1972).
Each chapter in Aroused is fascinating. For example, Epstein describes the discovery of human growth hormone and its early applied use in making short kids taller. Epstein also discusses the longstanding practice of surgically altering intersex children-children born with both male and female anatomical attributes-into "normal" boys or girls, often with devastating results. She traces the increasingly accepted use of sex hormone therapy, which allows a person who doesn't identify with the gender assigned them at birth to transition to the gender they feel they are.
In the fields of medicine and nursing, what we know constantly expands, and health care trends and practices evolve. Ultimately, as Aroused shows, the data and knowledge gained through scientific research and critical thinking lead to the best care for patients. That's something nurses will always feel good about.