Margaret Lautz

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OBJECTIVE Insulin represses the expression of gluconeogenic genes at the mRNA level, but the hormone appears to have only weak inhibitory effects in vivo. The aims of this study were 1) to determine the maximal physiologic effect of insulin, 2) to determine the relative importance of its effects on gluconeogenic regulatory sites, and 3) to correlate those(More)
Whether serotonin (5-hydroxytryptamine [5-HT]) enhances net hepatic glucose uptake (NHGU) during glucose infusion was examined in conscious 42-h-fasted dogs, using arteriovenous difference and tracer ([3-(3)H]glucose) techniques. Experiments consisted of equilibration (-120 to -30 min), basal (-30 to 0 min), and experimental (0-390 min) periods. During the(More)
OBJECTIVE Insulin-mediated suppression of hepatic glucose production (HGP) is associated with sensitive intracellular signaling and molecular inhibition of gluconeogenic (GNG) enzyme mRNA expression. We determined, for the first time, the time course and relevance (to metabolic flux) of these molecular events during physiological hyperinsulinemia in vivo in(More)
Portal glucose delivery enhances net hepatic glucose uptake (NHGU) relative to peripheral glucose delivery. We hypothesize that the sympathetic nervous system normally restrains NHGU, and portal glucose delivery relieves the inhibition. Two groups of 42-h-fasted conscious dogs were studied using arteriovenous difference techniques. Denervated dogs (DEN;(More)
The importance of hypothalamic insulin action to the regulation of hepatic glucose metabolism in the presence of a normal liver/brain insulin ratio (3:1) is unknown. Thus, we assessed the role of central insulin action in the response of the liver to normal physiologic hyperinsulinemia over 4 h. Using a pancreatic clamp, hepatic portal vein insulin delivery(More)
OBJECTIVE We previously showed that elevating hepatic nitric oxide (NO) levels reduced net hepatic glucose uptake (NHGU) in the presence of portal glucose delivery, hyperglycemia, and hyperinsulinemia. The aim of the present study was to determine the role of a downstream signal, soluble guanylate cyclase (sGC), in the regulation of NHGU by NO. RESEARCH(More)
The purpose of this study was to determine the effect of liver glycogen loading on net hepatic glycogen synthesis during hyperinsulinemia or hepatic portal vein glucose infusion in vivo. Liver glycogen levels were supercompensated (SCGly) in two groups (using intraportal fructose infusion) but not in two others (Gly) during hyperglycemic-normoinsulinemia.(More)
Diabetic patients treated with inhaled insulin exhibit reduced fasting plasma glucose levels. In dogs, insulin action in muscle is enhanced for as long as 3 h after insulin inhalation. This study was designed to determine whether this effect lasts for a prolonged duration such that it could explain the effect observed in diabetic patients. Human insulin was(More)
We examined the extent to which priming the liver with a pulse of Humulin or the insulin analog hexyl-insulin monoconjugate 2 (HIM2) reduces postprandial hyperglycemia. Somatostatin (0.5 microg.kg(-1).min(-1)) was given with basal intraportal insulin and glucagon for 4.5 h into three groups of 42-h-fasted conscious dogs. From 0-5 min, group 1 (BI, n = 6)(More)
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