What is the Origin of Nocturnal Hormones?

The term combines 'nocturnal' (from Latin nocturnalis, pertaining to night) and 'hormones' (Greek hormon, to set in motion), clearly denoting their time-dependent release pattern. The clinical importance of this category emerged with the discovery of melatonin's role as the "darkness hormone" and the recognition of the significant nocturnal surge of growth hormone, highlighting sleep as a critical endocrine event.

What is the Mechanism of Nocturnal Hormones?

The secretion of nocturnal hormones is primarily driven by the suprachiasmatic nucleus (SCN), the body's master clock, which responds to the absence of light. Melatonin release from the pineal gland is directly inhibited by light and surges in the dark, acting as a signal for sleep onset and synchronizing other rhythms. Simultaneously, the deep sleep state triggers the HPS axis to release large pulses of GH, mediated by a shift in GHRH and Somatostatin tone, thereby driving overnight cellular repair and protein synthesis.

Nocturnal Hormones

Meaning

Nocturnal hormones are the cohort of endocrine signaling molecules whose secretion patterns are fundamentally tied to the sleep-wake cycle and peak during the hours of darkness. Key examples include melatonin, which orchestrates the circadian rhythm, and Growth Hormone (GH), which is released in large, pulsatile bursts during deep, slow-wave sleep to facilitate repair and regeneration. The proper secretion of these hormones is essential for anabolic processes, immune function, and the detoxification pathways that occur overnight. Clinical evaluation of these hormones often requires timed, specialized collection protocols to capture their peak activity.