Plasma NEFA Levels Research Articles

Observations on some effects of L-triiodothyronine on carbohydrate and lipid metabolism in man.

Fasting serum lipid levels and changes in plasma glucose, fatty acid non-esterified (Nefa), and blood pyruvate levels during intravenous glucose tolerance tests were measured in 13 normal subjects before and one, five, and 15 days after the administration of 1-triiodothyronine (T3) calculated as 6 mug/kg body weight. Significant increases in the mean basal metabolic rate and the mean fasting plasma Nefa level occurred within 10 to 17 hours of a single dose of T3, while a rise in the mean fasting plasma glucose concentration just failed to achieve significance. Fasting concentrations of blood pyruvate and serum triglyceride were unaffected. A significant fall in serum cholesterol levels was produced and lasted at least five days. All other indices returned to normal by five days.During intravenous glucose tolerance tests performed at intervals after T3 administration no change in plasma glucose levels from control values was seen. Mean plasma Nefa and blood pyruvate levels, however, were significantly raised above control values during the early stages of the test 10 to 17 hours after T3. The relationship between these findings and those observed in clinical thyrotoxicosis is discussed.

Some effects of 3-chloroisoxazole-5-carboxylic acid on lipid and carbohydrate metabolism

The effect of 3-chloroisoxazole-5-carboxylic acid (CIC) on lipid and carbohydrate metabolism has been investigated. CIC lowered plasma NEFA levels in fasted glucose-primed rats and was significantly more active than 5-methylpyrazole-3-carboxylic acid (MPC). Both CIC and MPC had hypoglycaemic activity. With both CIC and MPC the fall in plasma NEFA always preceded the fall in blood sugar levels. CIC and MPC reduced the blood sugar and plasma NEFA in alloxan diabetic rats. CIC and MPC inhibited the basal and adrenaline and growth hormone stimulated NEFA release from in vitro rat epididymal fat pads. This CIC inhibition of growth hormone stimulated NEFA release was confirmed in intact rabbits. It seems that both MPC and CIC inhibit triglyceride breakdown in adipose tissue and that the effect upon blood glucose levels is probably secondary to the effect on fat metabolism.

Effect of oral contraceptives on carbohydrate metabolism

Longitudinal studies of plasma glucose, non-esterified fatty acids (Nefa), and insulin and blood pyruvate levels during oral and intravenous glucose tolerance tests are described in three groups of women treated with combined oral contraceptive preparations: (A) 91 women tested before and during therapy; (B) 39 women tested during therapy and again after this had been discontinued; and (C) 22 women tested twice during therapy. The mean fasting plasma glucose level was unchanged during therapy. In terms of the total area between the plasma-glucose curve and the abscissa, oral and intravenous glucose tolerance deteriorated during therapy in 78% and 70% of group A women, respectively. Thirteen per cent of group A women developed chemical diabetes mellitus during therapy. In group B, oral glucose tolerance improved in 90% and intravenous glucose tolerance improved in 85% after therapy was discontinued. Group C, with an initial mean oral glucose tolerance similar to that of group B during therapy, showed no significant mean change of oral glucose tolerance on retesting. Mean plasma Nefa levels, both before and after oral or intravenous glucose, were unchanged during therapy in groups A and B. During therapy the mean fasting blood pyruvate level was raised in group A and mean blood pyruvate levels were also higher in both groups during oral and intravenous glucose tolerance tests. The mean fasting plasma insulin levels were unchanged during therapy in both groups, but plasma insulin levels were significantly raised in group A after oral and intravenous glucose. Mean plasma insulin levels during oral and intravenous glucose tolerance tests in group B, however, were not significantly different on and off therapy. It is suggested that the impaired glucose tolerance is `steroid diabetes9 caused by raised plasma cortisol (hydrocortisone) levels secondary to the oestrogen component of the oral contraceptive. The clinical consequences of these abnormalities remain to be determined. Some individual case studies are presented which exemplify the metabolic abnormalities described above.

Effect of Nicotinic Acid Administration on Plasma Growth Hormone Concentrations.

SummarySerial plasma glucose, NEFA, and HGH concentrations were measured in normal male subjects following saline injection (Group 1, 9 cases), nicotinic acid injection (Group 2, 5 cases), and nicotinic acid plus heparin injection (Group 3, 4 cases) for 180 minutes. There was no appreciable change of plasma glucose in all groups. In Group 1 there was no significant change of plasma, NEFA and HGH. In Group 2, plasma NEFA showed an initial decrease followed by the secondary rise at 180 minutes, and plasma HGH showed a marked rise at 120 minutes and/or at 180 minutes. In Group 3, plasma NEFA did not show significant reduction and plasma HGH showed no significant changes. From the results obtained, it was suggested that the lowering of plasma NEFA levels by nicotinic acid administration can stimulate the secretion of HGH, and an assumption was made that plasma NEFA could be at least one of the factors in regulating HGH secretion. It was also suggested that plasma HGH may, at least in part, participate in indu...

Feeder lamb response to cortisone acetate and diethylstilbestrol.

Three experiments were conducted to determine the effects of cortisone acetate (CA) in combination with diethylstilbestrol (DES) upon rate of gain and carcass characteristics of feeder lambs. Results of experiment I indicate that wether lambs injected three times weekly with 100 mg. of CA and fed 2 mg, of DES daily did not differ significantly (P<.05) in rate of gain or carcass grade from wethers receiving only DES. Adrenal gland weights were significantly (P<.01) decreased by CA treatment. In experiment II, wethers fed DES had similar liveweight gains but significantly (P<.05) lower carcass grades than wethers fed DES plus 44 mg. CA. Nitrogen retention, plasma NEFA and plasma glucose levels were not significantly (P<.10) affected by the feeding of CA. In experiment III, DES significantly (P<.05) decreased gains of ewe lambs in comparison with controls. Gain depression did not occur when ewes were fed 44 or 88 mg. of CA per kg. of ration along with DES. Gains of wethers fed these CA levels plus DES did not differ significantly (P<.05) from wethers receiving only DES. Carcass grades of ewe and wether lambs fed the combination of CA and DES did not differ significantly (P<.05) from lambs receiving DES only.

Effects of prolonged fasting on insulin secretion.

The effects of total starvation upon response to glucose and tolbutamide were studied in obese nondiabetic and in obese diabetic individuals. Response was determined by serial measurement of plasma insulin, glucose, NEFA, and beta-hydroxybutyrate levels. In confirmation of other reports, obese diabetics had significantly greater plasma insulin responses to glucose and tolbutamide prefasting. Following a prolonged fast, obese nondiabetics developed increased insulin resistance manifested by impaired glucose tolerance without significant change in plasma insulin response. In contrast, obese diabetics had little further deterioration in glucose tolerance or increase in insulin resistance. In both groups studied, the response of blood glucose and plasma insulin levels to tolbutamide was unaltered by caloric deprivation. Carbohydrate intolerance of fasting appeared best explained by increased contra-insulin factors and decreased islet cell responsiveness to glucose. Fasting, for at least seven days, failed to reproduce in the nondiabetic obese individuals the patterns of response to glucose and tolbutamide seen in obese diabetic subjects.

Influence of exogenous growth hormone on endogenous growth hormone release.

SummaryPituitary content of growth hormone was determined in rats submitted to insulin hypoglycemia, pretreated or not treated with bovine growth hormone. Exogenous growth hormone was capable of inhibiting endogenous growth hormone release, suggesting the existence of an “auto” feed-back mechanism. A close interrelationship was also observed between plasma NEFA levels and growth hormone secretion.

Corticotropin-Induced Hyperlipemia in Rabbits.

Summary and conclusionRepeated subcutaneous injections or intravenous infusion of corticotropin A1 in rabbits caused prompt elevation of plasma NEFA levels, accumulation of fat in the liver and kidneys, and hyperlipemia. These responses appear to be evoked by extra-adrenal action of corticotropin A1.

Blood ketone and plasma nefa levels in the immediate post-operative period

Blood ketone bodies and plasma NEFA have been estimated before, during, and after operation in an attempt to determine when overall body metabolism starts to use fat in the quantities indicated by clinical experience. It is concluded from the data that the carbohydrate reserve is depleted earlier in patients awaiting operation than would be the case in simple starvation. The failure of blood ketones and plasma NEFA to show a sustained rise post-operatively (as found in fasting subjects) is thought to be due to the avidity of the tissues for these energy substrates, so that increased utilisation outstrips increased production during the first day after operation. There would seem to be a place for intravenous fat emulsions in post-operative therapy in selected cases where there is evidence of insufficient endogenous caloric reserve.

Studies on nonesterified fatty acids in diabetes mellitus

I measured the NEFA level of plasma in 98 diabetic patients by the Dole's method and persued the relationship between NEFA and carbohydrate metabolism experimentally.1) Foundamental experimentThe plasma NEFA level and blood sugar decreased with the administration of insulin in vivo, while with the administration of glucose the plasma NEFA level decreased and blood sugar increased.In vitro, the adipose tissue of rat releases NEFA. The rate of evolution of NEFA increased by the addition of adrenalin to the medium and decreased by the addition of insulin or glucose.The plasma NEFA level elevated in the Vitamin B1, B2, B6 and Pantothenic acid deficient rats. It was conceivable that the carbohydrate metabolism was impaired by these Vitamin deficiencies and its deficient energy was supplemented from the depot fat.2) Clinical experimentIn normal subject, the plasma NEFA level was found to be between 400 and 800 μEq./L. with the average of 637 μEq./L.. In diabetic patients, the plasma NEFA level tended to elevate at the average level of 740μEq./L.. Particurally in severe diabetic patients, whose blood sugar levels were over 200 mg/dl, the plasma NEFA level averaged 989μEq./L. and remarkably elevated in the cases with ketonuria.There was no correlation between the elevation of plasma NEFA level and the duration of diabetes mellitus. Also no intimate relationship between the vascular complication and the plasma NEFA level was found.After the treatment with insulin, sulfonylurea and DBI, the abnormality of plasma NEFA level was improved and insulin was most effective. The treatment with pyridoxal phosphate in diabetic patient with vascular complications showed the improvement of metabolic defects in diabetes and the decrease of high plasma NEFA level. However, with the administration of dextran sulfate, the plasma NEFA level increased and the lipoprotein lipase activity increased. This indicated that the plasma NEFA level increased by the increased lipoprotein lipase activity. So the administration of dextran sulfate in diabetic patients with vascular complications may be effective in order to improve or to protect arteriosclerosis.From these results, it is obvious that the plasma NEFA level has an intimate relationship with the carbohydrate metabolism. It was assumed that the measurement of plasma NEFA is important in order to know the carbohydrate and fat metabolism disorders in diabetes.

Failure of hypophysectomy, adrenalectomy or thyroidectomy to affect response of nonesterified fatty acids to fasting.

SummaryThere is no evidence of diurnal variation of plasma NEFA levels in rats. Hypophysectomized, adrenalectomized and thyroidectomized animals show significantly lower plasma NEFA values than normal rats either when food is provided ad lib. or after fasting. After 16 hour fast, both normal and operated rats show marked increase in plasma NEFA levels. It is probable that the mechanism involved in NEFA response to fasting is not controlled by pituitary, thyroid or adrenal hormones.

Response of plasma NEFA levels to epinephrine infusions in normal and obese women.

ConclusionThese observations suggest, then, that there is no impairment in ability of fat stores in obese patients to release NEFA in response to epinephrine.

Effect of Intravenous Amino Acids on Plasma Non-Esterified Fatty Acids.

(1) The effect of infusing an amino acid mixture (protein hydrolysate) on plasma NEFA, venous glucose level, and capillary-venous glucose difference, was studied in 6 healthy volunteer subjects. In every instance, plasma NEFA levels fell precipitously during amino acid infusion, and capillary-venous glucose differences increased concurrently. Similar results were obtained when a single amino acid, L-arginine, was infused in 2 normal subjects. (2) The results suggest that NEFA-lowering effects of parenterally administered amino acids may have been mediated entirely or in part via an induced increase in rate of glucose utilization.