Modeling of free fatty acid dynamics: insulin and nicotinic acid resistance under acute and chronic treatments

The relationship between the rate of lipolysis and rate of glucose production (Ra) was investigated in 14- and 86-h fasted humans. [6,6-2H]glucose and [2H]5glycerol were infused to measure glucose and glycerol Ra in response to infusions of nicotinic acid in 14- and 86-h fasted subjects (protocol 1). The response of glucose Ra to nicotinic acid alone and nicotinic acid plus unlabeled glycerol was also measured in 86-h fasted subjects (protocol 2). After a 14-h fast, nicotinic acid caused a 30% decrease in plasma insulin levels and a marked (66%) decrease in plasma free fatty acid levels but did not have any significant effect on glucose Ra and concentration. After 86 h of fasting, nicotinic acid decreased glycerol Ra and hence lipolytic rate by approximately 60%. This caused a significant decrease (P less than 0.05) of 16-20% in glucose Ra and uptake. This decrease in glucose Ra was abolished when unlabeled glycerol was also infused with nicotinic acid to maintain glycerol Ra. These findings suggest that, in normal humans, a decrease in the rate of lipolysis regulates glucose Ra via its effect on the availability of glycerol for gluconeogenesis.

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Effects of noradrenaline and nicotinic acid on plasma free fatty acids and oxygen consumption in cold-adapted rats

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y79-109 ◽

1979 ◽

Vol 57 (7) ◽

pp. 725-730 ◽

Cited By ~ 5

Author(s):

Louise Lafrance ◽

Danièle Routhier ◽

Bernard Têtu ◽

Christian Têtu

Keyword(s):

Fatty Acids ◽

Oxygen Consumption ◽

Fatty Acid ◽

Free Fatty Acid ◽

Nicotinic Acid ◽

Free Fatty Acids ◽

Simultaneous Increase ◽

Elevated Plasma ◽

Cold Adapted ◽

Plasma Ffa

A 3-h noradrenaline (NA) infusion (1.5 μg kg−1 min−1) produced a sustained enhanced oxygen consumption (O2 cons.) in cold-adapted rats. Plama free fatty acid (FFA) levels were elevated by NA in control and in cold-adapted rats, but to a lesser extent in cold-adapted rats; the increase was maintained at a plateau in both groups during the entire period of NA infusion. A 1-h nicotinic acid (Nic A) infusion (1.5 mg kg−1 min−1) added to the NA infusion inhibited the calorigenic response to NA in cold-adapted rats and reduced the elevated plasma FFA concentration in control and in cold-adapted rats to values below basal levels. However, when the Nic A infusion was stopped, the O2 cons, was increased again in cold-adapted rats by the uninterrupted NA infusion, without the simultaneous increase of the plasma FFA concentration; the plasma FFA concentration was maintained in cold-adapted rats below basal values and merely brought back to basal levels in control rats. From these results, it is suggested that plasma FFA are not an essential substrate to the calorigenic response to NA observed in cold-adapted rats, as 85% of the response can occur when the plasma FFA concentration is very low.

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Growth Hormone, Cortisol, and Glucagon Concentrations during Plasma Free Fatty Acid Depression: Different Effects of Nicotinic Acid and an Adenosine Derivative (BM 11.189)*

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem-57-2-410 ◽

1983 ◽

Vol 57 (2) ◽

pp. 410-414 ◽

Cited By ~ 22

Author(s):

HANS-JÜRGEN QUABBE ◽

ALFRED S. LUYCKX ◽

MANFRED L’AGE ◽

CORNELIUS SCHWARZ

Keyword(s):

Growth Hormone ◽

Fatty Acid ◽

Free Fatty Acid ◽

Nicotinic Acid ◽

Plasma Free Fatty Acid

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INFLUENCE OF SERUM FREE FATTY ACID LEVELS ON GROWTH HORMONE SECRETION IN LACTATING COWS

Journal of Endocrinology ◽

10.1677/joe.0.0660213 ◽

1975 ◽

Vol 66 (2) ◽

pp. 213-224 ◽

Cited By ~ 33

Author(s):

R. REYNAERT ◽

M. DE PAEPE ◽

S. MARCUS ◽

G. PEETERS

Keyword(s):

Growth Hormone ◽

Fatty Acid ◽

Free Fatty Acid ◽

Nicotinic Acid ◽

Glucose Concentration ◽

Hormone Secretion ◽

Growth Hormone Secretion ◽

Direct Consequence ◽

Serum Free Fatty Acid ◽

Lactating Cows

SUMMARY The influence of intravenous injections or infusions of insulin (0·2 i.u./kg), propranolol (150 mg), 3,5-dimethylpyrazole (3 mg/kg), 3,5-dimethylisoxazole (0·08 mg/kg), glucose (0·5 g/kg), nicotinic acid (120 mg/kg), arginine (0·5 g/kg) or butyrate (0·5 mmol/kg) on plasma glucose levels, and on serum concentrations of growth hormone and free fatty acids of lactating cows was investigated. In all of these experiments we noted an increase in the level of growth hormone. This increase was not a direct consequence of alterations in the glucose concentration, since the growth hormone peak occurred both during a decrease (insulin, 3,5-dimethylisoxazole, nicotinic acid and butyrate tests), and during an increase of the glucose level (glucose, arginine and propranolol tests), whereas the glucose concentration remained unchanged during the 3,5-dimethylpyrazole experiments. However, in each instance a precipitous fall of the free fatty acid level was noted. The glucose, growth hormone, and free fatty acid levels of lactating cows were not affected by either i.v. injection or infusion of saline.

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