What is the Origin of Pulsatile Growth Hormone Secretion?

This is a fundamental concept in neuroendocrinology, established through continuous blood sampling studies that revealed the non-linear, rhythmic nature of GH release, which is controlled by the hypothalamic hormones Growth Hormone-Releasing Hormone (GHRH) and somatostatin. The term describes the specific temporal pattern of secretion.

What is the Mechanism of Pulsatile Growth Hormone Secretion?

The mechanism is regulated by the interplay of GHRH, which stimulates GH release, and somatostatin, which inhibits it, creating a precise push-pull system that generates the characteristic pulses. The intermittent nature of the secretion is critical because it ensures that the GH receptors on target cells, such as hepatocytes and muscle cells, remain sensitive and responsive to the hormone's signaling. Disruption of this pulsatility compromises the systemic effects of GH.

Pulsatile Growth Hormone Secretion

Meaning

The natural, intermittent release of Growth Hormone (GH) from the anterior pituitary gland in distinct bursts or pulses throughout the 24-hour cycle, rather than a continuous steady stream. The largest and most significant pulses typically occur shortly after sleep onset, particularly during the deep sleep phase. This pulsatile pattern is essential for GH’s biological activity, as it prevents receptor downregulation and maximizes its anabolic and lipolytic effects.