Arteriovenous differences across human adipose and forearm tissues after overnight fast.

Measurements of arteriovenous differences across subcutaneous abdominal tissue (mainly adipose) and deep forearm tissue (mainly muscle) were made on 25 occasions in normal subjects after an overnight fast. Adipose tissue was shown to be strongly lipolytic (releasing nonesterified fatty acids and glycerol), to clear circulating triacylglycerol, glucose, ketone bodies and acetate, and to produce lactate. Uptake of circulating carbohydrate and ketones was sufficient to account for only 51% of the adipose tissue oxygen consumption, implying that adipose tissue utilizes fuel(s) stored within it.

Effects of insulin on human adipose tissue metabolism in vivo.

1. The metabolic effects of insulin on human adipose tissue were studied by combining the euglycaemic clamp technique with measurement of arteriovenous differences across the subcutaneous adipose tissue of the anterior abdominal wall. 2.

Plasma triacylglycerol extraction in human adipose tissue in vivo: effects of glucose ingestion and insulin infusion.

Extraction of endogenous triacylglycerol (TAG) was measured across the subcutaneous adipose tissue of the abdominal wall and across forearm muscle in 16 studies on 13 normal subjects. After overnight fast there was significant TAG extraction across both adipose tissue (4 per cent) and muscle (1 per cent). After 75 g oral glucose (8 subjects), there was a rise in the arterial TAG concentration to a peak at 60 min, with a concomitant increase in extraction across adipose tissue (to 9 per cent).

Metabolic characteristics of human adipose tissue in vivo.

1. A method was developed for sampling the venous drainage from the subcutaneous adipose tissue of the anterior abdominal wall. This is a large depot in many subjects, and seems well suited to such studies as it is completely separated from the venous drainage of the underlying muscle by the aponeurosis of the external oblique muscle.

Changes in forearm blood flow at elevated ambient temperature and their role in the apparent impairment of glucose tolerance.

1. Antecubital venous plasma glucose and insulin concentrations after ingestion of 75 g of glucose were higher in six normal subjects when studied at an ambient temperature of 33 degrees C at an ambient temperature of 23 degrees C; the mean area under the glucose-time curve increased from 833 at 23 degrees C to 990 mmol min-1 at 33 degrees C, that for insulin from 5300 to 7900 m-units min 1-1. 2.

Effect of acetate infusion on energy expenditure and substrate oxidation rates in non-diabetic and diabetic subjects.

Sodium acetate was infused intravenously at 2.5 mmoles/min for 60 min into 6 normal subjects and 6 non-insulin dependent diabetic patients. In control experiments the same subjects received equimolar sodium bicarbonate infusions.

Effects of chronic endotoxaemia on oxygen consumption at different ambient temperatures in the unanaesthetised rat.

Oxygen consumption has been measured at different ambient temperatures at intervals during the intravenous infusion of endotoxin (1 mg/kg.day-1) from a subcutaneously implanted osmotic minipump in unanaesthetised rats. On day 1 of the infusion oxygen consumption was elevated at ambient temperatures of 10, 28, and 31 degrees C but not at 20 degrees C, compared with pair-fed saline-infused controls.

Energy metabolism during chronic endotoxin infusion in the rat, with special reference to free fatty acid turnover.

We have studied various aspects of whole-body energy metabolism during chronic endotoxin infusion in the rat. In particular, we studied free fatty acid kinetics using bolus injections of 14C-palmitate. The general response to 7 days of chronic endotoxin infusion could be divided into an initial 3- to 4-day period of illness with loss of appetite, followed by rapid recovery.

Hormonal and metabolic responses to glucose infusion in sepsis studied by the hyperglycemic glucose clamp technique.

Although nutritional support is vital to treatment of severe sepsis, the septic patient does not respond normally to glucose infusion. We have used the hyperglycemic glucose clamp technique to investigate the initial hormonal and metabolic responses of the septic patient to glucose under controlled conditions. The plasma glucose concentration was raised to and maintained at 12 mmol/liter for 2 hr in 12 septic patients and 11 normal controls.

Oral glucose tolerance and ambient temperature in non-diabetic subjects.

When either a 960-kcal, 140-g carbohydrate meal, or a 75-g glucose load was ingested by non-diabetic Caucasians, the 2-h venous plasma glucose concentration was higher by 0.82 and 1.25 mmol/l, respectively, if the ambient temperature was 33 degrees C rather than 23 degrees C.

Factors affecting the plasma insulin concentration shortly after accidental injury in man.

There are conflicting reports on plasma insulin concentrations in the acutely injured. Plasma insulin and glucose concentrations have been measured in 504 patients within 8 h of injury, and related to the severity of injury as assessed by the injury severity score (ISS). As in previous surveys of injured patients, an extremely wide range of insulin concentrations was found (2-141 mU/l).

Use of alumina columns to prepare plasma samples for liquid-chromatographic determination of catecholamines.

We describe an improved method of sample preparation for liquid chromatographic determination of plasma catecholamines. The catecholamines are extracted from plasma by using small, cheaply-made columns of alumina, with or without prior clean-up on commercially available ion-exchange columns. Advantages of this technique over the conventional batch-extraction method of using alumina are speed, convenience, and improved sample clean-up.

The disposal of intravenous glucose studied using glucose and insulin clamp techniques in sepsis and trauma in man.

Whole body glucose uptake and oxidation during a hyperglycemic clamp have been shown to be depressed in hypermetabolic septic patients compared to control subjects despite similar plasma insulin concentrations. Forearm glucose uptake was similarly impaired. Metabolic rate was not increased further by the glucose infusion in the patients although a 20% rise was elicited in the controls.

Plasma catecholamines in the acute phase of the response to myocardial infarction.

Plasma catecholamine (adrenaline, noradrenaline and dopamine) concentrations have been measured in 48 patients within 6 hours of the onset of symptoms of an acute myocardial infarction. The concentrations of all three catecholamines were elevated, and there were positive correlations between plasma noradrenaline concentrations and the severity of infarct as assessed by the coronary prognostic index and serum LDH levels. Plasma glucose, free fatty acid, lactate and cortisol levels were elevated while insulin levels were reduced.