Hormonal regulation of adrenal function occurs primarily through activation of GPCRs. GPCRs are central to many of the body's endocrine and neurotransmitter pathways. Recently it was shown that activation of GPR103 by its ligand QRFP induced feeding, locomotor activity and metabolic rate, and QRFP is bioactive in adipose tissue of obese individuals. Given that the adrenal gland is pivotal organ for energy balance and homeostasis we hypothesised that GPR103 and QRFP are involved in steroidogenic responses. Using qRT-PCR and immunohistochemistry we mapped both GPR103 and QRFP in human fetal and adult adrenal gland as well as rat adrenals. Both were primarily localised in the adrenal cortex but not in the medulla. Activation of GPR103 in human adrenocortical H295R cells led to a decrease in forskolin-increased cAMP and increase of intracellular Ca⁺⁺ levels. In addition, treatment of H295R cells with QRFP induced aldosterone and cortisol secretion as measured by ELISA. These increases were accompanied by increased expression and activity of StAR, CYB11B1 and CYP11B2 as assessed by qRT-PCR and luciferase-reporter assay respectively. Using specific inhibitors we also demonstrated that the aldosterone induction involves MAPK, PKC and/or T-type Ca⁺⁺ channel dependent pathways. These novel data demonstrate that QRFP induces adrenal steroidogenesis in vitro by regulating key steroidogenic enzymes involving MAPK/PKC and Ca⁺⁺ signalling pathways.