The “metabolic sensor” function of rat supraoptic oxytocin and vasopressin neurons is attenuated during lactation but not in diet-induced obesity
Year: 2015
Type: article
Abstract: The oxytocin (OT) and vasopressin (VP) neurons of the supraoptic nucleus (SON) demonstrate characteristics of "metabolic sensors". They express insulin receptors and glucokinase (GK). They respond to an increase in glucose and insulin with an increase in intracellular [Ca(2+)] and increased OT and VP release that is GK dependent. Although this is consistent with the established role of OT as an anorectic agent, how these molecules function relative to the important role of OT during lactation and whether deficits in this metabolic sensor function contribute to obesity remain to be examined. Thus, we evaluated whether insulin and glucose-induced OT and VP secretion from perifused explants of the hypothalamo-neurohypophyseal system are altered during lactation and by diet-induced obesity (DIO). In explants from female day 8 lactating rats, increasing glucose (Glu, 5 mM) did not alter OT or VP release. However, insulin (Ins; 3 ng/ml) increased OT release, and increasing the glucose concentration in the presence of insulin (Ins+Glu) resulted in a sustained elevation in both OT and VP release that was not prevented by alloxan, a GK inhibitor. Explants from male DIO rats also responded to Ins+Glu with an increase in OT and VP regardless of whether obesity had been induced by feeding a high-fat diet (HFD). The HFD-DIO rats had elevated body weight, plasma Ins, Glu, leptin, and triglycerides. These findings suggest that the role of SON neurons as metabolic sensors is diminished during lactation, but not in this animal model of obesity.
Language: English
Subfield: Endocrine and Autonomic Systems
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
Funders: American Physiological Society, National Institutes of Health, National Cancer Institute, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Child Health and Human Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development
Awards: G196677508, Postnatal Actions of Maternal Obesity on Neonatal Metabolic Health, G2970922064, A Narrowed Window for Targeting Metabolic Flexibility in Breast Cancer Prevention, Functional Development of the Mammary Gland, G6639068597, G8317730232, Bioenergetic and Metabolic Consequences of the Loss of Gonadal Function, Colorado Nutrition Obesity Research Center
OpenAlex ID: W2277583222