Role of hypothalamic paraventricular nucleus α- and β-adrenergic receptors in regulation of blood glucose, free fatty acids and corticosterone

摘要: Abstract The potential roles of adrenergic and noradrenergic terminals in the hypothalamic paraventricular nucleus regulation blood glucose free fatty acids, two major metabolic fuels, were examined. Corticosterone was also measured, both to assess specificity any effects for because endogenous catecholamines this site have previously been implicated corticosterone regulation. In first experiment adult male albino rats having chronically implanted guide cannulae aimed at or caudate received microinjections agonists methoxamine ( α 1 , clonidine 2 ), isoproterenol (β) (0, 10, 30, 100 nmol/500 nl), samples taken from tail tip. second a different set 30 nmol vehicle subcutaneously instead brain microinjections. Intracranial produced marked moderate hyperglycemia, respectively; did not alter glucose. For neither nor there difference hyperglycemia as function microinjection site: also, subcutaneous injections same peak response found after dose. Free acid levels increased by isoproterenol, but slightly suppressed methoxamine; agonist effects, β effect, greater than microinjections; into nuclei equivalent elevations. These results suggest that most, if all, hyperglycemic can be ascribed leakage material vasculature, with subsequent action distant site. contrast, all 3 seem capable acting within levels. on agonists, agonist, appear due, least part, actions brain. Previous suggestions catecholamine are directly strongly involved fuel may require reconsideration.