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M H Laudat

Publications and source records attributed to M H Laudat.

At least 55 records · Page 3Linked to original sources
PubMed1978

Stimulation of triacylglycerol synthesis in rat adipocytes by plasma very-low-density lipoproteins.

The effect of human plasma lipoproteins on lipogenesis from glucose has been studied in isolated rat adipocytes. The very-low-density lipoproteins increased lipogenesis specifically, whereas low-density lipoproteins and high-density lipoproteins were without effect. Such stimulation could be reproduced with partially delipidated very-low-density lipoproteins. Nod-esterified fatty acids and glycerol were also without effect. Pretreatment of the adipocytes with trypsin did not alter the effect of very-low-density lipoprotein. The presence of Ca2+ was required for the full activation of lipogenesis. The synthesis of acylglycerol fatty acids and of acylglycerol glycerol were equally increased. The effect of very-low-density lipoprotein was not additive to that of insulin. It is suggested that very-low-density lipoprotein may directly stimulate lipogenesis in fat-cells, particularly in states when the lipoproteins are present at high concentration in the circulation.

Adipose Tissue↗
PubMed1978

Insulin and growth hormone secretion in dialyzed children: influence of dietary manipulation.

The insulin and growth hormone responses to arginine and the growth hormone response to insulin were studied in 10 children undergoing chronic hemodialysis 1) under usual dietary prescription and 2) after 7 days of dietary manipulation (DM) decreasing mean carbohydrate intake from 48 to 36% and increasing lipid intake from 42 to 54% (percent of total energy) with the polyunsaturated/saturated fatty acids ratio being increased from 0.2 to 2. Mean fasting insulin and growth hormone were significantly decreased after DM: 10.3 +/- 3 muunits/ml and 19.9 +/- 3.5 ng/ml before and 4.3 +/- 0.8 muunits/ml and 9.3 +/- 2.4 ng/ml after DM. The mean arginine-induced insulin peak and the growth hormone peaks after arginine and insulin remained very high after DM. There was no decrease of mean plasma triglycerides: 214 +/- 30 mg/dl before and 237 +/- 26 mg/dl after DM. However, two children who had the greatest decrease in carbohydrate intake exhibited a decrease of triglycerides and of arginine-induced insulin secretion. The percent variation of insulin area after DM was significantly correlated with the percent variation of plasma triglycerides.

Adolescent↗
PubMed1975

An impaired response of adenylate cyclase to stimulation by epinephrine in adipocyte plasma membranes from genetically obese mice (ob/ob).

The present studies have established that there is an impaired response to epinephrine of the adenylate system in adipocyte preparations from obese hyperglycemic mice as compared to their thin littermates. In contrast, membrane preparations from both groups of animals were found to exhibit a similar response to fluoride ion. The response of adenylate cyclase to epinephrine was enhanced to a similar extent by increasing the ATP concentration in adipocyte plasma membranes from the two groups of animals. While GTP (0.1 muM) elicited an ATP-like response of similar magnitude in adenylate cyclase activity in both membrane preparations, it did not therefore abolish the impaired response to epinephrine of adenylate cyclase activity in membranes of obese mice. The response of adenylate cyclase activity to (--)-epinephrine in membrane preparations from obese mice progressively diminished with the age of these animals. In contrast, the concentration of (--)-epinephrine required for half-maximal stimulation of adenylate cyclase was similar and remained unchanged with the age for both membrane preparations. These data suggest that a perturbation may occur in the coupling step between the hormone receptor and the catalytic site of the adenylate cyclase system in obese mice. While a 15-day restrictive diet or a 72-h period of fasting was found to normalize the hyperinsulinemia of obese animals, neither affected the response of adenylate cyclase to epinephrine in preparations of adipocyte membranes from these mice. These results suggest that the observed defect in the response of plasma membrane adenylate cyclase activity to epinephrine in obese mice does not result from their hyperinsulinism.

Adenosine Triphosphate↗
PubMed1968

[Urinary lipids].

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Adolescent↗