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

Characterisation of a novel primate-specific 11b-hydroxysteroid dehydrogenase called 11bHSD1L in the ovary (#41)

Timothy J Cole 1 , Daniel A Bird 1 , Kuan Liew 1 , Gareth G Lavery 2
  1. Monash University, Clayton, Vic, Australia
  2. CEDAM, University of Birmingham, Birmingham, UK

Endocrine steroid hormones including estrogens, androgens, glucocorticoids and mineralocorticoids play clinically important and specific regulatory roles in human development, growth, metabolism, reproduction and brain function. The 11-beta hydroxysteroid dehydrogenase enzymes have key roles in the pre-receptor modification of glucocorticoids, modifications that directly regulate blood pressure, fluid and electrolyte homeostasis, as well as modulating metabolic and brain function. A recent analysis of the human genome has located a novel largely uncharacterized 11bHSD-like gene on human chromosome 19q13.3, a distinct gene from the very well characterized 11bHSD1 (human chromosome 1q32-q41) and 11bHSD2 (human chromosome 16q22) genes. Strikingly, a search in other mammalian genomes has revealed the complete absence of this third 11bHSD gene from the mouse, rat and rabbit genomes. This human 11-beta-hydroxysteroid dehydrogenase 1-like protein (HSD11B1L) gene and its encoded enzyme are completely uncharacterized for substrate specificity and detailed cellular expression pattern. The human HSD11B1L gene is encoded by 9 exons and analysis of EST library transcripts indicates the use of two alternate ATG start-sites in exons 2 & 3, and alternative RNA splicing in exon 9. HSD11B1L shares a 40% amino acid sequence homology with 11bHSD1 and the strong conservation of the NAD+/NADP+ nucleotide binding and dehydrogenase/reductase catalytic site domains.. Preliminary data demonstrates high expression of this enzyme in two human and non-human primate tissues, the ovary and brain. The endogenous substrate of this enzyme is unknown but we intriguingly show that it is unlikely to be cortisol or cortisone.