What is the Origin of Hormone Signaling Molecules?

The concept of hormones as chemical messengers originated with the work of Bayliss and Starling in the early 20th century, who coined the term "hormone" from the Greek hormao, meaning "I excite" or "I set in motion." Subsequent endocrinology research meticulously characterized the molecular structures and receptor interactions of these signaling molecules, forming the foundation of modern hormonal science.

What is the Mechanism of Hormone Signaling Molecules?

The mechanism of action is receptor-mediated and varies based on the molecule's structure. Steroid hormones, being lipid-soluble, typically diffuse across the cell membrane to bind to intracellular receptors, directly influencing gene transcription. Peptide hormones, being water-soluble, bind to receptors on the cell surface, triggering secondary messenger systems, such as cAMP or protein kinases, to rapidly modify cellular function and enzyme activity.

Hormone Signaling Molecules ∞ Area

Hormone Signaling Molecules

Meaning

Hormone Signaling Molecules are the diverse chemical messengers—including peptides, steroids, and amines—that are secreted by endocrine glands and travel through the bloodstream to exert their effects on distant target cells. These molecules bind to specific receptors, initiating a cascade of intracellular events that regulate physiological processes such as growth, metabolism, reproduction, and mood. Their proper function is the basis of all endocrine health and communication.