Exogenous glucocorticoids upregulate preference for sweet in sand rat, Psammomys obesus

Psammomys obesus, widely known as sand rat, develops obesity during captivity. To assess the role of confinement stress on metabolic alterations and sweet taste perception, the gustatory cue involved in obesity, we administered corticosterone (CORT) intraperitoneally in male Psammomys obesus to yield a stressful condition. CORT administration was found to increase preference for sweet solutions in a two bottle-choice paradigm in these animals. Moreover, CORT administration increased the messenger ribonucleic acid (mRNA) expression of sweet test receptor in fungiform taste bud cells. As regards liver, CORT increased mRNA expression encoding glucose-6-phosphatase (G-6-P), phosphoenolpyruvate carboxykinase 1 (PEPCK1) and stearoyl-CoA desaturase-1 (SCD-1). Interestingly, CORT decreased gut peptide YY (PYY), insulin, and triglyceride levels in the blood. Our study demonstrates that corticosterone, known to be released during the captivity period, might play a key role in the development of obesity by influencing sweet taste perception, release of a gut peptide and modifications in lipid/glucidic metabolic enzymatic pathways in Psammomys obesus.