Isolated segments of renal tubules prepared from rat kidney cortex were capable of sustained rates of gluconeogenesis when lactate served as substrate. An increase in external Ca(++), or the addition of parathyroid hormone at a fixed Ca(++) concentration led to enhanced rate of gluconeogenesis. However, parathyroid did not increase gluconeogenesis in the absence of external Ca(++) even though i...

High-fat feeding has been shown to cause hepatic insulin resistance. The aims of this study were to investigate the biochemical steps responsible for enhanced gluconeogenesis as a result of increased dietary fat intake and the site or sites at which the antihyperglycemic agent metformin acts to inhibit this process. Male Hooded Wistar rats were fed either a standard chow diet (5% fat by weight)...

OBJECTIVE Measurement of plasma C2 glucose enrichment is cumbersome. Therefore, the plasma C5 glucose-to-(2)H(2)O rather than the plasma C5-to-C2 glucose ratio commonly has been used to measure gluconeogenesis and glycogenolysis during hyperinsulinemic-euglycemic clamps. The validity of this approach is unknown. RESEARCH DESIGN AND METHODS Ten nondiabetic and 10 diabetic subjects ingested (2)...

The responses of livers from rats with type 2 diabetes to alanine (gluconeogenesis and ammonia detoxification) and other gluconeogenic substrates were investigated. The experimental system was the isolated perfused rat liver. Neonatal type 2 diabetes was induced with streptozotocin. Ammoniogenesis from endogenous substrates was 610% higher in livers from diabetic rats when compared to the contr...

Incubation of hepatocytes from 24 h-starved rats in the presence of 0.5 mM-adenosine decreased gluconeogenesis from lactate, but not from alanine. The inhibition of gluconeogenesis was associated with a stimulation of ketone-body production and an inhibition of pyruvate oxidation. These metabolic changes were suppressed in the presence of iodotubercidin (an inhibitor of adenosine kinase), but w...

NH,CI. None of the adaptations could be attributed to the high-protein diet per se since they were not evident in those rats fed a high-protein diet and given NaHC03 solution to drink. Of particular interest is the increased rate of gluconeogenesis found in kidney slicesfrom rats fed ona high-protein diet. Krebs et al. (1963) have observed an increased rate of renal gluconeogenesis in rats fed ...

1. Gluconeogenesis from pyruvate was measured in renal-cortical-tubules fragments prepared from fed male rats 6-8 days after adrenalectomy or sham adrenalectomy. The response of this process to 3':5'-cyclic AMP and adrenaline was compared in these two states at two Ca2+ concentrations. 2. Adrenalectomy decreased the percentage stimulation of gluconeogenesis by 3':5'-cyclic AMP, but increased pe...

Gluconeogenesis is a complex metabolic process that involves multiple enzymatic steps regulated by myriad factors, including substrate concentrations, the redox state, activation and inhibition of specific enzyme steps, and hormonal modulation. At present, the most widely accepted technique to determine gluconeogenesis is by measuring the incorporation of deuterium from the body water pool into...

Isoproterenol and norepinephrine (10(-4) M) significantly increased cyclic AMP formation and glucose production by the isolated tubules of the renal cortex of the rat. These effects were abolished by propranolol. Theophylline diminished the effects of the catecholamines on gluconeogenesis despite a marked augmentation in cyclic AMP concentration. In the absence of calcium ion in the incubation ...