Pyruvate kinase activity and the rates of gluconeogenesis and glycolysis in rat hepatocytes were evaluated by production of glucose and lactate + pyruvate from dihydroxyacetone during a feeding cycle or progressive starvation. In fed rats, during daylight (low food intake) and until darkness, gluconeogenesis progressively increased and glycolysis decreased slightly, but gluconeogenesis never ex...

Dysregulation of gluconeogenesis is a key pathological feature of type 2 diabetes. However, the molecular mechanisms underlying the regulation of gluconeogenesis remain unclear. Bhalla et al. recently reported that cyclin D1 suppresses hepatic gluconeogenesis through CDK4-dependent phosphorylation of PGC1alpha and consequent inhibition of its activity. The cyclin D1-CDK4 might thus serve as an ...

Leptin and insulin share some hypothalamic signaling molecules, but their central administration induces different effects on hepatic glucose fluxes. Acute insulin infusion in the third cerebral ventricle inhibits endogenous glucose production (GP), whereas acute leptin infusion stimulates gluconeogenesis but does not alter GP because of a compensatory decrease in glycogenolysis. Because melano...

1. The drug phenyl ethyl biguanide (PEBG) was used in vivo and in vitro to study further the relationship between renal gluconeogenesis and ammonia production in the rat. 2. When PEBG was injected intraperitoneally into the rats, it caused a decrease in urinary ammonia in spite of a greater degree of systemic acidosis. PEBG injections also blocked the increase in glucose and ammonia production ...

Investigations on the metabolic role of the Wnt signaling pathway and hepatic transcription factor 7-like 2 (TCF7L2) have generated opposing views. While some studies demonstrated a repressive effect of TCF7L2 on hepatic gluconeogenesis, a recent study using liver-specific Tcf7l2(-/-) mice suggested the opposite. As a consequence of redundant and bidirectional actions of transcription factor (T...

BACKGROUND Fetal energy demands are met mostly from oxidation of maternally supplied glucose. In pregnant adults this increased glucose requirement is met by an increase in gluconeogenesis. It is not known, however, whether, like their adult counterparts, pregnant adolescent girls can increase gluconeogenesis-hence, glucose production. OBJECTIVE Our objective was to measure glucose kinetics i...

In preterm infants, both hypo- and hyperglycemia are a frequent problem. Intravenous lipids can affect glucose metabolism by stimulation of gluconeogenesis by providing glycerol, which is a gluconeogenic precursor, and/or free fatty acids (FFA), which are stimulants of the rate of gluconeogenesis. In 25 preterm infants, glucose production and gluconeogenesis were measured using stable isotope t...

The role of mitochondrial phosphoenolpyruvate carboxykinase in both hepatic and renal gluconeogenesis was studied in the chicken since this species reportedly lacks the cytosolic enzyme. Lactate is the major substrate used for glucose synthesis in isolated chicken hepatocytes but pyruvate, glycerol, and some amino acids, as well as lactate, are converted to glucose in isolated chicken kidney tu...

Android obesity is associated with increased cortisol secretion. Direct effects of cortisol on gluconeogenesis and other parameters of insulin resistance were determined in normal subjects. Gluconeogenesis was determined using the reciprocal pool model of Haymond and Sunehag (HS method), and by the Cori cycle/lactate dilution method of Tayek and Katz (TK method). Glucose production (GP) and glu...

Mao, Catherine S., Sara Bassilian, Shu K. Lim and W.-N. Paul Lee. Underestimation of gluconeogenesis by the [U-C6]glucose method: effect of lack of isotope equilibrium. Am J Physiol Endocrinol Metab 282: E376–E385, 2002. First published October 16, 2001; 10.1152/ajpendo.00210.2001.— Among the many tracer methods to indirectly estimate gluconeogenesis in humans, the [U-C6]glucose method as propo...