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Updated: Jan 25, 2026

Computer-Generated Animal Model Stimuli
Published on: July 29, 2007
The tammar wallaby: a non-traditional animal model to study growth axis maturation
Jennifer A Hetz1, Brandon R Menzies2, Geoffrey Shaw3
1School of BioSciences, The University of Melbourne, Vic. 3010, Australia; and Escuela de Agronomía, Pontificia Universidad Católica de Valparaíso, Casilla 4-D, Quillota, Región de Valparaíso, Chile.
Abstract:
Maturation of the growth hormone (GH)/insulin-like growth factor 1 (IGF1) axis is a critical developmental event that becomes functional over the peripartum period in precocial eutherian mammals such as sheep. In mice and marsupials that give birth to altricial young, the GH/IGF1 axis matures well after birth, suggesting that functional maturation is associated with developmental stage, not parturition. Recent foster-forward studies in one marsupial, the tammar wallaby (Macropus eugenii), have corroborated this hypothesis. 'Fostering' tammar young not only markedly accelerates their development and growth rates, but also affects the timing of maturation of the growth axis compared with normal growing young, providing a novel non-traditional animal model for nutritional manipulation. This review discusses how nutrition affects the maturation of the growth axis in marsupials compared with traditional eutherian animal models.
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