Rapid maturation of the endocrine growth axis in the marsupial during development

Abstract

Growth hormone is essential for post-natal growth and its actions are triggered by the upregulation of hepatic growth hormone receptors (GHRs) after birth in eutherian mammals. In utero, fetal growth is largely driven by the availability of nutrients that control the relative levels of insulin and insulin-like growth factors (IGFs). This study examined expression of hepatic GHR, IGF-1, IGF-2 and IGF binding protein-3 (IGFBP-3) from late fetal stages of pregnancy through pouch life to weaning using the tammar wallaby. The advantage of the tammar wallaby is that it gives birth to an altricial young that is only 0.1% of adult female size, essentially an exteriorized fetus. After 9 months of pou..