Cholecystokinin (CCK), a gastrointestinal (GI) hormone, is also present in structures of the central nervous system such as cortex, hippocampus, amygdala, olfactory tubercle and in regions involved in the regulation of the pituitary function. Although a number of studies have evaluated the effects of CCK on hypothalamic-pituitary-adrenal (HPA) axis function and on arginine vasopressin (AVP), prolactin (PRL) and growth hormone (GH) plasma levels in the laboratory animal, its role in humans has not been explored. Hence, we examined the effects of the exogenous administration of this GI hormone on corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), cortisol, AVP, PRL and GH plasma levels in humans. To accomplish this, graded doses (0, 50, 140 and 420 ng/kg) of sulfated CCK octapeptide (CCK-8), the full biologically active peptide, were infused intravenously to healthy men in 30 min. Blood samples were collected 30 min and immediately before the infusion was started (baseline) and 15, 30, 45, 60 and 90 min thereafter. CRH, ACTH, and AVP were extracted from plasma proteins using cartridges of SepPak C18. These hormones and cortisol were measured by radioimmunoassay whereas PRL and GH were measured by immunoradiometric assay. CCK-8 increased plasma ACTH and cortisol levels only at the dose of 420 ng/kg, whereas it had no detectable effect on plasma CRH levels. It increased also plasma AVP levels at the doses of 140 and 420 ng/kg. However, this effect reached the statistical significance only at the highest dose tested. CCK-8 stimulated PRL and GH release in a dose-dependent fashion. The lowest stimulatory dose was 140 ng/kg for both hormones. In conclusion, these results suggest that CCK is capable of stimulating HPA axis function, AVP, PRL and GH release in humans. Because these endocrine effects of CCK were detected at doses higher than that found able to mimic postprandial levels of this hormone, to produce Gl-related effects, and to modulate the release of GI hormones, we speculate that CCK, released by the GI tract, may not play a physiologic role in the regulation of the pituitary function in humans.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.