Abstract:
Small size in mammals usually restricts long-term, frequent monitoring of endocrine
function using plasma as a matrix. Thus, the non-invasive monitoring of hormone metabolite
concentrations in excreta may provide an invaluable approach. The aim of the current study was
to examine the suitability of enzyme immunoassays (EIAs) for monitoring responses to stressors
in the naked mole-rat (Heterocephalus glaber, NMR) using urine and feces as hormone matrices.
A saline control administration, and a high- and low-dose adrenocorticotropic hormone (ACTH)
challenge were performed on six male and six female disperser morph NMRs. The results revealed
that a 5α-pregnane-3β,11β,21-triol-20-one EIA detecting glucocorticoid metabolites (GCMs) with
a 5α-3β-11β-diol structure is the most suitable assay for measuring concentrations in male urine
samples, whereas an 11-oxoaetiocholanolone EIA detecting GCMs with a 5β-3α-ol-11-one structure
appears the most suitable EIA for quantifying GCMs in female urine. An 11-oxoaetiocholanolone
EIA detecting 11,17 dioxoandrostanes was the most suitable EIA for quantifying GCMs in the feces of
both sexes. There were sex-related differences in response to the high- and low-dose ACTH challenge.
We recommend using feces as a more suitable matrix for non-invasive GCM monitoring for NMRs
which can be valuable when investigating housing conditions and other welfare aspects.
Description:
DATA AVAILABILITY: Data supporting the reported results will be sent by the corresponding
author upon request.
SUPPLEMENTARY MATERIALS : TABLE S1: Summary of saline volume and synthetic
adrenocorticotropic hormone (Synacthen® depot, Novartis, South Africa (Pty) Ltd.) administered to
each individual during the ACTH challenge; TABLE S2: Summary of EIA sensitivities and intra-assay
and inter-assay coefficients of variation in high- and low-value quality controls for all EIAs applied to
measure immunoreactive urine glucocorticoid metabolite (uGCM) and fecal glucocorticoid metabolite
in naked mole-rats.
