3β-HSD expression in the CNS of a manakin and finch

Author(s)
Joy Eaton, Devaleena S Pradhan, Julia Barske, Leonida Fusani, Virginie Canoine, Barney A Schlinger
Abstract

The prohormone, dehydroepiandrosterone (DHEA) circulates in vertebrate blood with the potential for actions on target tissues including the central nervous system (CNS). Many actions of DHEA require its conversion into more active products, some of which are catalyzed by the enzyme 3β-hydroxysteroid-dehydrogenase/isomerase (3β-HSD). Studies of birds show both expression and activity of 3β-HSD in brain and its importance in regulating social behavior. In oscine songbirds, 3β-HSD is expressed at reasonably high levels in brain, possibly linked to their complex neural circuitry controlling song. Studies also indicate that circulating DHEA may serve as the substrate for neural 3β-HSD to produce active steroids that activate behavior during non-breeding seasons. In the golden-collared manakin (Manacus vitellinus), a sub-oscine bird, low levels of courtship behavior are displayed by males when circulating testosterone levels are basal. Therefore, we asked whether DHEA circulates in blood of manakins and whether the brain expresses 3β-HSD mRNA. Given that the spinal cord is a target of androgens and likely important in regulating acrobatic movements, we also examined expression of this enzyme in the manakin spinal cord. For comparison, we examined expression levels with those of an oscine songbird, the zebra finch (Taeniopygia guttata), a species in which brain, but not spinal cord, 3β-HSD has been well studied. DHEA was detected in manakin blood at levels similar to that seen in other species. As described previously, 3β-HSD was expressed in all zebra finch brain regions examined. By contrast, expression of 3β-HSD was only detected in the manakin hypothalamus where levels were greater than zebra finches. In spinal cord, 3β-HSD was detected in some but not all regions in both species. These data point to species differences and indicate that manakins have the substrate and neural machinery to convert circulating DHEA into potentially active androgens and/or estrogens.

Organisation(s)
Department of Behavioral and Cognitive Biology
External organisation(s)
University of California, Los Angeles, Veterinärmedizinische Universität Wien
Journal
General and Comparative Endocrinology
Pages
43-49
ISSN
0016-6480
DOI
https://doi.org/10.1016/j.ygcen.2017.09.016
Publication date
01-2018
Peer reviewed
Yes
Austrian Fields of Science 2012
106051 Behavioural biology
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/3hsd-expression-in-the-cns-of-a-manakin-and-finch(3342084a-031e-4242-aaa6-fc7bfc5f68a1).html