What is the Origin of Hormonal Signals?

The concept is a core tenet of endocrinology, deriving from the Greek word "hormao," which translates to "I excite" or "I set in motion." The classical definition of a hormone was established in the early 20th century, describing a substance secreted into the blood to exert its effects on remote tissues. This foundational definition has since been expanded to include localized paracrine and autocrine signaling pathways.

What is the Mechanism of Hormonal Signals?

Hormonal signals exert their effects by binding to highly specific protein receptors located either on the cell surface or within the cytoplasm and nucleus of their target cells. This precise binding event initiates a cascade of intracellular biochemical events, known as signal transduction, which ultimately modifies cellular function, alters gene expression, or regulates enzyme activity. The high specificity of the receptor ensures that each hormone elicits the correct physiological response in the appropriate tissue.

Hormonal Signals

Meaning

Hormonal signals are the precise chemical messages transmitted by hormones, which are secreted by endocrine glands into the systemic circulation to regulate the function of distant target cells and organs. These signals collectively form the body’s essential, systemic communication network, coordinating complex physiological processes such as energy metabolism, growth and development, reproduction, and the integrated stress response. The accuracy and pulsatile nature of these signals are absolutely critical for maintaining systemic homeostasis and adaptive capacity.