Phenobarbital and Insulin Reciprocate Activation of the Nuclear Receptor Constitutive Androstane Receptor through the Insulin Receptor

• Published in: The Journal of pharmacology and experimental therapeutics Vol. 357; no. 2; pp. 367 - 374
• Main Authors: Yasujima, Tomoya, Saito, Kosuke, Moore, Rick, Negishi, Masahiko
• Format: Journal Article
• Language: English
• Published: United States The American Society for Pharmacology and Experimental Therapeutics 01.05.2016
• Subjects: Animals; Aryl Hydrocarbon Hydroxylases - metabolism; Blood Glucose - metabolism; Cytochrome P-450 CYP2B6 - drug effects; Cytochrome P450 Family 2; Hepatocytes - drug effects; Hypoglycemic Agents - pharmacology; Insulin - pharmacology; Male; Metabolism, Transport, and Pharmacogenomics; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Knockout; Phenobarbital - pharmacology; Receptor Cross-Talk - drug effects; Receptor, Insulin - drug effects; Receptors, Calcium-Sensing; Receptors, G-Protein-Coupled - agonists; Receptors, G-Protein-Coupled - genetics; Steroid Hydroxylases - metabolism; Transfection
• ISSN: 1521-0103; 0022-3565; 1521-0103
• DOI: 10.1124/jpet.116.232140

Phenobarbital (PB) antagonized insulin to inactivate the insulin receptor and attenuated the insulin receptor downstream protein kinase B (AKT)-forkhead box protein O1 and extracellular signal-regulated kinase 1/2 signals in mouse primary hepatocytes and HepG2 cells. Hepatic AKT began dephosphorylation in an early stage of PB treatment, and blood glucose levels transiently increased in both wild-type and constitutive androstane receptor (CAR) knockout (KO) mice. On the other hand, blood glucose levels increased in wild-type mice, but not KO mice, in later stages of PB treatment. As a result, PB, acting as an insulin receptor antagonist, elicited CAR-independent increases and CAR-dependent decreases of blood glucose levels at these different stages of treatment, respectively. Reciprocally, insulin activation of the insulin receptor repressed CAR activation and induction of its target CYP2B6 gene in HepG2 cells. Thus, PB and insulin cross-talk through the insulin receptor to regulate glucose and drug metabolism reciprocally.