Food intake and meal pattern in IAPP knockout mice with and without infusion of exogenous IAPP

Abstract

Objective. The current study used islet amyloid polypeptide (IAPP) knockout mice (KO mice) to investigate the physiological role of IAPP in the regulation of food intake (FI). Material and methods. FI and body weight were measured in KO and wild-type (WT) mice for 27 weeks. In an additional short-term experiment, IAPP (25 pmol·kg^-1min^-1) was infused subcutaneously for 3 days in KO and WT mice, and FI, meal pattern, and body weight were analyzed. Results. In the long-term experiment, no significant differences in body weight were seen between WT and KO mice at any point. FI, meal number, and meal size did not differ significantly between the groups in any of the five selected weeks that were studied. In the short-term experiment, FI decreased significantly during IAPP infusion in both WT and KO groups. FI was significantly lower in the KO mice compared with WT on days 1 and 2 (p < 0.05 and p < 0.01, respectively). Conclusions. The data showing no differences in FI and body weight were seen between KO and WT mice, indicating that FI can be controlled in the absence of IAPP. The more marked anorectic effect seen in the KO mice during IAPP infusion suggests that IAPP receptors and/or IAPP post-receptor signaling pathways are up-regulated in mice lacking endogenous IAPP.

Key Words::

• body weight
• eating
• food intake
• IAPP knockout mouse
• meal pattern
• satiety

Acknowledgements

The authors acknowledge the skillful technical assistance of Beth Hagman. This work was supported by the Swedish Medical Research Council (K2003-73X-1265506A), the Swedish Society of Medicine (Svenska Läkaresällskapet), and the KI Research Foundations.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.