Endocrine glands

Abstract

Gland, from the French glande (itself derived from Old French glandre), refers to clusters of cells that produce specific secretions. The word has had more exotic meanings beyond the realms of biology and medicine—the sleeves that encased Victorian piston rods, for instance, and the acorn-shaped lead missiles used by ancient Romans. In medicine, at least since the 19th century, glands have been of two types—with ducts and without. The ductless or endocrine (from the Greek endon, meaning “inside”) pour their secretions directly into the blood, and so affect the whole organism. In 1905, the British physiologist Ernest H Starling, after consultations with Cambridge classicists, named those secretions “hormones” (from the Greek hormao, meaning “to excite”).Although the existence of endocrine glands had long been known to anatomists, little was known about their functions before the late 19th century. Research on endocrine glands took off after the sensational claim by the septuagenarian French-American physiologist Charles-Edouard Brown-Séquard (1817–94) that he had “rejuvenated” himself by injections of canine testicular extracts. Testicular substances had long been used in folk remedies to improve virility and that reputation now received a scientific boost. There was much serious research on endocrine physiology and the interest in rejuvenation also continued. By the 1920s, several procedures were available that purported to enhance the secretory powers of ageing testicles. Faith in glandular therapy was deepened by the undeniable efficacy of thyroid extract in myxoedema and insulin in diabetes. The endocrine system was thought to have much more to offer, and gland extracts were prescribed for disorders as diverse as learning difficulties, infertility, haemophilia, and obesity.The futility of most of these treatments had become only too apparent by the late 1930s. By then, glandular interventions were being superseded by the administration of pure, standardised hormones. Although some of the grand therapeutic dreams of the 1920s survived into the new hormonal age, they were no longer associated with the word “gland”, which now retreated into the thickets of histological terminology from where it had been drawn out by Brown-Séquard and his successors barely half a century earlier. Gland, from the French glande (itself derived from Old French glandre), refers to clusters of cells that produce specific secretions. The word has had more exotic meanings beyond the realms of biology and medicine—the sleeves that encased Victorian piston rods, for instance, and the acorn-shaped lead missiles used by ancient Romans. In medicine, at least since the 19th century, glands have been of two types—with ducts and without. The ductless or endocrine (from the Greek endon, meaning “inside”) pour their secretions directly into the blood, and so affect the whole organism. In 1905, the British physiologist Ernest H Starling, after consultations with Cambridge classicists, named those secretions “hormones” (from the Greek hormao, meaning “to excite”). Although the existence of endocrine glands had long been known to anatomists, little was known about their functions before the late 19th century. Research on endocrine glands took off after the sensational claim by the septuagenarian French-American physiologist Charles-Edouard Brown-Séquard (1817–94) that he had “rejuvenated” himself by injections of canine testicular extracts. Testicular substances had long been used in folk remedies to improve virility and that reputation now received a scientific boost. There was much serious research on endocrine physiology and the interest in rejuvenation also continued. By the 1920s, several procedures were available that purported to enhance the secretory powers of ageing testicles. Faith in glandular therapy was deepened by the undeniable efficacy of thyroid extract in myxoedema and insulin in diabetes. The endocrine system was thought to have much more to offer, and gland extracts were prescribed for disorders as diverse as learning difficulties, infertility, haemophilia, and obesity. The futility of most of these treatments had become only too apparent by the late 1930s. By then, glandular interventions were being superseded by the administration of pure, standardised hormones. Although some of the grand therapeutic dreams of the 1920s survived into the new hormonal age, they were no longer associated with the word “gland”, which now retreated into the thickets of histological terminology from where it had been drawn out by Brown-Séquard and his successors barely half a century earlier.