Dynamics of energy regulation and weight control

Authors

  • Jacqueline A. Ick-Joson National Institute of Molecular Biology and Biotechnology, University of the Philippines Diliman
  • Francis Isidore G. Totanes National Institute of Molecular Biology and Biotechnology, University of the Philippines Diliman
  • Cynthia P. Palmes-Saloma National Institute of Molecular Biology and Biotechnology, University of the Philippines Diliman

Abstract

We have generated obese mice in our laboratory exhibiting an adult-onset type of obesity. These mice originate from a serendipitously generated agouti line that in turn appeared after nitrate-induced mutations at the albino locus of an albino founder population. These pigmented mice, observed to be hyperactive, were otherwise normal in gross morphology. Brother-sister mating of this agouti line resulted in the emergence of mouse liters exhibiting different coat colors, namely, albino, agouti (brown-black), and black. We have observed that several black mice generated from this agouti line become obese upon maturity.
The agouti obesity syndrome, a spectrum of metabolic disorders, has been previously described in obese agouti mice, suggesting the possibility of a close interaction between agouti-related gene signaling and the regulation of hyperactive behavior in our mice on one hand, and the obese phenotype on the other. Current studies of molecules involved in the agouti obesity syndrome has shown cross-regulation between proteins involved in pigmentation, via the melanocortin-receptor signaling pathway, and proteins involved in regulating energy expenditure and feeding behavior. The agouti locus, which encodes a peptide expressed in the skin, modifies coat color by antagonizing the melanocyte stimulating hormone receptor, MCR-1. The obesity associated with the agouti-yellow mouse is the consequence of an ectopic expression of the agouti protein in the brain. The melanocyte-stimulating hormone receptor, MCR-4, is localized in the hypothalamus and is implicated in the regulation of feeding behavior and metabolism. The primary modality in which agouti induces obesity has been demonstrated to be through chronic antagonism of the MCR-4. The results we have so far generated suggest that the agouti coat color in mice with the hyperactive phenotype and the obesity in succeeding generations are linked and must involve regulation of energy balance and body weight taking place in higher brain centers, particularly in the hypothalamus.

Downloads

Issue

Article ID

SPP-2000-ID-07

Section

Interdisciplinary Studies

Published

2000-10-27

How to Cite

[1]
JA Ick-Joson, FIG Totanes, and CP Palmes-Saloma, Dynamics of energy regulation and weight control, Proceedings of the Samahang Pisika ng Pilipinas 18, SPP-2000-ID-07 (2000). URL: https://proceedings.spp-online.org/article/view/SPP-2000-ID-07.