Chang GR, Chiu YS, Wu YY, Lin YC, Hou PH, Mao FC. Rapamycin impairs HPD-induced beneficial effects on glucose homeostasis.
Br J Pharmacol 2015;
172:3793-804. [PMID:
25884889 PMCID:
PMC4523336 DOI:
10.1111/bph.13168]
[Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 03/08/2015] [Accepted: 04/07/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE
Rapamycin, which is used clinically to treat graft rejection, has also been proposed to have an effect on metabolic syndrome; however, very little information is available on its effects in lean animals/humans. The purpose of this study was to characterize further the effects of the continuous use of rapamycin on glucose homeostasis in lean C57BL6/J mice.
EXPERIMENTAL APPROACH
Mice were fed a high-protein diet (HPD) for 12 weeks to develop a lean model and then were treated daily with rapamycin for 5 weeks while remaining on a HPD. Metabolic parameters, endocrine profiles, glucose tolerance tests, insulin sensitivity index, the expression of the glucose transporter GLUT4 and chromium distribution were measured in vivo.
KEY RESULTS
Lower body weight gain as well as a decreased caloric intake, fat pads, fatty liver scores, adipocyte size and glucose tolerance test values were observed in HPD-fed mice compared with mice fed a high-fat or standard diet. Despite these beneficial effects, rapamycin-treated lean mice showed greater glucose intolerance, reduced insulin sensitivity, lower muscle GLUT4 expression and changes in chromium levels in tissues even with high insulin levels.
CONCLUSION AND IMPLICATIONS
Our findings demonstrate that continuous rapamycin administration may lead to the development of diabetes syndrome, as it was found to induce hyperglycaemia and glucose intolerance in a lean animal model.
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