Abstract
With the aim to reveal common genomic regions influencing phenotypes related to HPA
axis function and metabolism, we did a quantitative trait loci (QTL) study in a F2
population obtained from the cross-breeding between 2 contrasted rat strains, LOU/C
and Fischer 344. QTL determining phenotypes related first to corticotropic function
were searched: plasma corticosterone (Cort) in control and stress conditions, after
a dexamethasone suppression treatment (glucocorticoid receptor related-effect), and
mineralocorticoid receptor-mediated urinary response to aldosterone. Then, phenotypes
related to metabolism were studied on the same animals: body composition, basal and
post-insulin plasma glucose, plasma free fatty acids, leptin, and insulin. Finally,
we analyzed the overlapping regions between these QTL and looked for candidate genes
within these regions. The gene NR3C1 encoding the glucocorticoid receptor was confirmed
to be central in the link between hypothalamic-pituitary-adrenal (HPA) axis function
and fat deposition, and its metabolic consequences. Among the other candidate genes
detected, most contain a glucocorticoid responsive element, strengthening our hypothesis
of common genetic determinism between HPA axis and metabolism.
Key words
QTL - metabolism - glucocorticoid - rat