Clinical Significance:
Neurotensin is a 13 amino acid peptide produced primarily by endocrine cells of the ileal mucosa. Physiological actions of Neurotensin include hypertension, vasodilation, hyperglycemia, and inhibition of gastric motility. Its C-terminus is similar to Angiotensin I. It is a potent analgesic affecting hypothermia, muscle relaxation, and decreased motor activity. Pancreatic Polypeptide secretion is strongly stimulated by Neurotensin. Neurotensin appears to cause the release of Luteinizing Hormone-Releasing Hormone and Corticotropin Releasing Hormone effecting the release of Luteinizing Hormone, Follicle Stimulating Hormone, and ACTH but not Thyroid Stimulating Hormone or Growth Hormone. Neurotensin also stimulates pancreatic bicarbonate and intestinal secretion. Neurotensin levels are stimulated by food and Bombesin. Elevated levels have been found in pancreatic endocrine tumors, Oat Cell, Squamous Cell, and Adeno Carcinomas. Elevated levels have been found to cause watery diarrhea.
Reference Range:
50 – 100 pg/ml
Procedure:
Neurotensin is measured by direct radioimmunoassay.
Patient Preparation:
Patient should be fasting 10 – 12 hours prior to collecton of specimen. Patient should not be on any antacid medication or medications that affect gastroentero-intestinal function, if possible, for at least 48 hours prior to collection.
Specimen Collection:
Collect 10mL blood directly into ISI’s Z-tubeTM Preservative and separate as soon as possible. Freeze plasma immediately after separation. Special Z-tube is available from Inter Science Institute (ISI). Minimum specimen size is 1 ml.
Important Precaution:
Specimens for this assay must be collected using the Z-tube. Specimens must be shipped frozen; specimens are not stable at refrigerated or room temperatures. No other specimens are acceptable.
Special Specimens:
For tumor/tissue and various fluids (i.e. CSF, peritoneal, synovial, etc.) contact the Institute for requirements and special handling.
Shipping Instructions:
Ship specimens frozen in dry ice.
References:
1. A Schulkes, P Chick, H Wong, and JH Walsh. A Radioimmunoassay for Neurotensin in Human Plasma. Clinica Chimica Acta 125: 49, 1982.
2. RE Carraway, SP Mitra, GE Feurle, and NH Hickey. Presence of Neurotensin and Neuromedin N within a Common Precursor from a Human Pancreatic Neuroendocrine Tumor. Journal of Clinical Endocrinology and Metabolism 66: 1323, 1988.