Abstract
Corticotropin-releasing factor (CRF)-like immunoreactivity was measured by radioimmunoassay in human organs and a small cell carcinoma of the lung associated with typical ectopic adrenooorticotropic hormone (ACTH) syndrome. It was found to be distributed in the stomach, pancreas, adrenal gland and a tumor producing ACTH ectopically in a concentration less than one twentieth of that of the hypothalamus. CRF-like immunoreactivity was not detected in the lung and thyroid tissue under the conditions tested. A dilution curve of CRF-like immunoreactivity in tissue extracts paralleled that of synthetic human CRF. When tissue extract was subjected to gel chromatography on a Sephadex G-50 column, a major immunoreactive CRF emmerged in elution volumes consistent with synthetic human CRF.
To examine whether CRF plays a role in the control of gut function possibly through modulation of other gut peptides, synthetic ovine CRF (100 μg iv bolus, followed by 200 μg infusion over 100 min) was administered to six normal subjects following ingestion of a 450 kcal meal. There was no change in plasma insulin, glucagon, gastrin, glucose and triglycerides compared to the control infusion.
These results suggest that a material (s) closely related to CRF is present in the stomach, pancreas, adrenal gland and a tumor producing ACTH ectopically. However, the role of CRF in these tissues remains to be studied.
