Poster Presentation The Annual Scientific Meeting of the Endocrine Society of Australia and the Society for Reproductive Biology 2014

Nutritional manipulation of adipose tissue in the developing tammar wallaby  (#318)

Jennifer Hetz 1 , Geoff Shaw 1 , Brandon R Menzies 1 , Marilyn B Renfree 1
  1. Department of Zoology, The University of Melbourne, Victoria 3010, Australia

Developmental regulation of adipogenesis is highly responsive to alterations in nutrition and growth factors1 but the mechanisms involved are still poorly understood. Our marsupial model of development allows for extensive nutritional manipulation of adipose tissue growth and maturation during stages equivalent to the fetus of traditional models such as sheep2, 3, 4. We investigated the consequences of energy deprivation, energy excess and high fat diet on the growth and expression of key growth genes in adipose tissue. For the high fat diet, we supplemented pouch young with emu oil (supplemented group). For energy excess, we fostered forward pouch young to an older stage of lactation (foster group). For energy deprivation, we used young of primiparous females (small group). Fat mass content and percentage body fat was significantly higher in foster and supplemented young and significantly lower in small young (ANOVA, p<0.05) when compared to control animals using dual-energy x-ray absorptiometry. Both, insulin like growth factor -I and -II (IGF-I and IGF-II) are important for adipose tissue growth. Visceral fat IGF-I mRNA expression was significantly higher in the fostered group (REST, p<0.05) and, unexpectedly, visceral fat IGF-II mRNA expression was significantly higher in small young (REST, p<0.05). IGF-binding protein-2 (IGFBP2) might limit adipose expansion by inhibiting adipocyte differentiation. Visceral fat IGFBP2 mRNA expression was significantly lower in the supplemented group (REST, p<0.05) but not other groups. Furthermore, visceral fat mRNA expression of DLK1 (PREF1) (principal marker of preadipocytes) was significantly lower in both supplemented and fostered young (REST, p<0.05). Thus, nutrition in the young marsupial does affect adipogenesis and mRNA expression of the key growth factors that control it.

  1. Ali, A. T., Hochfeld, W. E., Myburgh, R., & Pepper, M. S. (2013). Adipocyte and adipogenesis. European journal of cell biology 92(6): 229-236.
  2. Trott J.L. et al. (2003) Biology of Reproduction 68: 929-36.
  3. Brandon, R. (2013). The Tammar Wallaby: A Model Organism for Fetal-Stage Growth Manipulation. International Journal of Evolution.
  4. Kwek J.H. et al. (2009) Mechanisms of Development 126: 449-63