Neuroendocrine

Neuroendocrine refers to cells or systems that integrate neural and hormonal signaling. Neuroendocrine cells arise from neural crest or endoderm and function as a bridge between the nervous system and the endocrine system. They typically receive neuronal stimulation and respond by secreting hormones, neuropeptides, or amines into the bloodstream, thereby influencing distant targets.

Key components include the hypothalamus, the pituitary gland forming the hypothalamic-pituitary axis, the adrenal medulla, the pineal gland, pancreatic islets, and enteroendocrine cells in the gut. These elements regulate processes such as metabolism, growth, reproduction, stress response, water balance, digestion, and circadian rhythms. The hypothalamus directs pituitary secretion with releasing and inhibiting hormones; pituitary hormones act on peripheral glands and tissues. The adrenal medulla releases catecholamines in response to sympathetic input. Enteroendocrine cells secrete hormones like gastrin, ghrelin, and glucagon-like peptide-1 (GLP-1) that coordinate digestion and energy homeostasis.

Development and signaling: neuroendocrine signaling uses neurohormones, including hypothalamic releasing hormones, vasopressin, oxytocin, and catecholamines. Neuroendocrine communication can be rapid and localized or slow and systemic, allowing integration of neural activity with endocrine responses.

Disorders and clinical relevance: Neuroendocrine tumors arise from neuroendocrine cells anywhere along the axis, often slow-growing but can be malignant. Diagnosis relies on biomarkers such as chromogranin A, imaging, and histology. Treatments include surgery, somatostatin receptor analogs, targeted therapies, chemotherapy, and radionuclide therapies such as peptide receptor radionuclide therapy (PRRT). Other conditions include dysregulation of the hypothalamic-pituitary axis, pituitary adenomas, pheochromocytoma, and various gastrointestinal endocrinopathies.