Impaired glucose tolerance after streptozotocin microinjection into the mediodorsal prefrontal cortex of the rat

Abstract

The mediodorsal prefrontal cortex (mdPFC) is a key structure of the central glucose-monitoring (GM) neural network. Previous studies indicate that intracerebral streptozotocin (STZ) microinjection-induced destruction of local chemosensory neurons results in feeding and metabolic alterations. The present experiments aimed to examine whether STZ microinjection into the mdPFC causes metabolic deficits. To do so, glucose tolerance test (GTT) and measurements of plasma metabolites were performed in STZ-treated or control rats. Intraperitoneal D-glucose load was delivered 20 min or 4 weeks following the intracerebral microinjection of STZ or saline (acute or subacute GTT, respectively). The STZ-treated rats displayed acute glucose intolerance: at the 120th min of the test, blood glucose level of these rats was significantly higher than that of the ones in the control group. When determining the plasma level of various metabolites, 30 min following the intracerebral STZ or saline microinjection, the triglyceride concentration of the STZ-treated rats was found to be reduced compared with that of the control rats. The GM neurons of the mdPFC are suggested to be involved in the organization of complex metabolic processes by which these chemosensory cells contribute to adaptive control mechanisms of the maintenance of homeostasis.

Enhancing effect of streptozotocin-induced insulin deficit on antitumor innate immune defense in rats

“…STZ was kindly provided by Department of Pharmaceutical Chemistry in University Pécs. As it well known, STZ can selectively destroy beta cells of the Langerhans-islet, so it is widely used to induce experimental typ-1 diabetes mellitus in animals [21][22][23]. Nine days before the blood test, 65mg/kg STZ was injected into the tail vein.…”