The hypothalamus, a cone-shaped brain structure, secretes tiny amounts of hormones. This chemical process signals other glands within the body to release additional hormones, regulating anything from hair growth to metabolism.
By the 1960s, researchers had long suspected – but been unable to prove – the hypothalamus’ role as a trigger in the hormonal process. It took 1.5 million sheep brains to find evidence.
From this cache of craniums, Roger Guillemin, the founder of neuroendocrinology, extracted a thyroid-regulating molecule called “thyrotropin-releasing hormone.”
A few years later, Guillemin’s team at the Salk Institute for Biological Studies isolated other substances from brain tissue, including hormones that control reproductive functions of the pituitary. This discovery contributed to breakthroughs in the treatment of fertility and prostate cancer.
Synthetic versions of other compounds isolated by Guillemin’s laboratory – including gonadotropin-releasing hormone, somatostatin and somatocrinin – have been integrated into treatments for tumors and endocrine disorders.