Regulation of lipogenesis in adipocytes independent effects of thyroid hormones, cyclic AMP and insulin on the uptake of deoxy-d-glucose

Correze, C.; Krug, Eva; Verhaegen, Martine; Nunez, Jacques

doi:10.1016/0005-2760(79)90095-x

Cited by 15 publications

(7 citation statements)

References 29 publications

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“…In the forearm muscles of hypothyroid patients, the sensitivity of glucose disposal to insulin was found to be normal (6), whereas in adipocytes isolated from hypothyroid patients and examined in vitro, the sensitivity of glucose oxidation to insulin was normal (11) and that of glucose transport was decreased (12). In rats made hypothyroid, the responsiveness of glucose disposal to insulin was decreased in muscle (13)(14)(15) but increased in adipocytes (16).…”

Section: Discussionmentioning

confidence: 93%

Insulin Action in Adipose Tissue and Muscle in Hypothyroidism

Dimitriadis

Mitrou

Lambadiari

et al. 2006

The Journal of Clinical Endocrinology & Metabolism

199

171

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Section: Discussionmentioning

confidence: 93%

Insulin Action in Adipose Tissue and Muscle in Hypothyroidism

Dimitriadis

Mitrou

Lambadiari

et al. 2006

The Journal of Clinical Endocrinology & Metabolism

199

171

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“…It should be noted that the impact of the hypothyroid state on isolated adipocyte metabolism appears greater in magnitude than on the isolated soleus muscle system, inasmuch as the latter did not appear to be af- (19,20), who found increased adipocyte glucose metabolism in thyroidectomized rats. Rats were rendered hypothyroid for periods similar to those employed in our studies before experiments were performed.…”

Section: Discussionmentioning

confidence: 96%

Effect of Thyroid Status on Insulin Action in Rat Adipocytes and Skeletal Muscle

Czech¹,

Malbon²,

Kerman³

et al. 1980

J. Clin. Invest.

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A B S T R A C T Isolated adipocytes and soleus muscles prepared from mature rats, rendered hypothyroid by a low iodine diet and propylthiouracil, markedly resisted the ability of insulin to increase glucose utilization. In adipocytes, the sum of basal D-(1-14C)-glucose conversion to CO2, glyceride-glycerol, and fatty acid was unaltered by hypothyroidism, although conversion to fatty acid was decreased. The response of each of these metabolic pathways to insulin at all concentrations tested was greatly diminished in hypothyroid rat adipocytes. 3-0-Methylglucose transport rates in the presence of insulin were not significantly different in adipocytes from hypothyroid as compared with euthyroid rats, although basal transport rates were significantly higher in the hypothyroid state. Lipolysis and cyclic AMP accumulation in adipocytes from hypothyroid rats in response to theophylline were markedly diminished compared with euthyroid controls, but insulin was about as effective in inhibiting lipolysis in these cells as in those derived from euthyroid animals. The binding of '251-insulin to adipocytes at several hormone concentrations was also shown to be unaffected by hypothyroidism.In soleus muscle, basal glucose conversion to H20 and glycogen was unaltered in the hypothyroid state, whereas insulin action on these pathways was markedly inhibited. The decrease in muscle insulin responsiveness was less marked than that observed in adipocytes. Uptake of either 2-deoxyglucose or Larabinose in the presence or absence of insulin The present studies were thus designed to investigate a possible effect of thyroid hormone on glucose use in these tissues. In addition, the influence of thyroid status on the responsiveness of these tissues to insulin action on hexose transport and metabolism was assessed. The data demonstrate a striking deficit in the capacity of fat and muscle derived from hypothyroid rats to use glucose in the presence of insulin. This decreased response of glucose use to insulin in hypothyroid rats appears to be related to decreased activity of intracellular enzymes involved in glucose catabolism rather than a defective insulin effector system.

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“…It has been reported previously that changes in the rates of glucose transport in adipocytes isolated from hypothyroid rats may depend on the age of the rats when the hypothyroid treatment was initiated [17,19]. For this reason, both young and older rats were made hypothyroid (the body weights after treatment were 106 + 2 g and 176 + 2 g, respectively) and the results were compared to those obtained with age and weight-matched controls.…”

Section: Resultsmentioning

confidence: 99%

“…In hypothyroid patients, after administration of either intravenous glucose or insulin, and in the perfused rat hindquarter, the rate of utilization of glucose is either normal or decreased [11][12][13][14][15][16]. The effects of insulin on glucose utilization in isolated adipocytes from hypothyroid patients or rats are variable: the rate of glucose utilization is reported to be normal, decreased or increased [17][18][19]. The effects of insulin on glucose utilization in skeletal muscle have been investigated in only one study: markedly decreased rates of glycolysis and glycogen synthesis in soleus muscles isolated from hypothyroid rats were reported [19].…”

mentioning

confidence: 99%

Effects of hypothyroidism on the sensitivity of glycolysis and glycogen synthesis to insulin in the soleus muscle of the rat

Dimitriadis

Leighton

Parry-Billings

et al. 1989

Biochemical Journal

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1. The effects of hypothyroidism on the sensitivity of glycolysis and glycogen synthesis to insulin were investigated in the isolated, incubated soleus muscle of the rat. 2. Hypothyroidism, which was induced by administration of propylthiouracil to the rats, decreased fasting plasma levels of free fatty acids and increased plasma levels of glucose but did not significantly change plasma levels of insulin. 3. The sensitivity of the rates of glycogen synthesis to insulin was increased at physiological, but decreased at supraphysiological, concentrations of insulin. 4. The rates of glycolysis in the hypothyroid muscles were decreased at all insulin concentrations studied and the EC50 for insulin was increased more than 8-fold; the latter indicates decreased sensitivity of this process to insulin. However, at physiological concentrations of insulin, the rates of glucose phosphorylation in the soleus muscles of hypothyroid rats were not different from controls. This suggests that hypothyroidism affects glucose metabolism in muscle not by affecting glucose transport but by decreasing the rate of glucose 6-phosphate conversion to lactate and increasing the rate of conversion of glucose 6-phosphate to glycogen. 5. The rates of glucose oxidation were decreased in the hypothyroid muscles at all insulin concentrations. INTRODUCTIONPrevious studies have suggested that thyroid hormones influence the effect of insulin on the rate of glucose metabolism: in hyperthyroidism, the sensitivity of the rate of glucose production to insulin is decreased [1][2][3][4][5][6] whereas that of glucose uptake by skeletal muscle is increased [4,7]; in hypothyroidism, the rate of glucose production from the liver is decreased [8][9][10][11]. However, the effects of hypothyroidism on the sensitivity and responsiveness of glucose utilization to insulin have not been systematically studied. In hypothyroid patients, after administration of either intravenous glucose or insulin, and in the perfused rat hindquarter, the rate of utilization of glucose is either normal or decreased [11][12][13][14][15][16]. The effects of insulin on glucose utilization in isolated adipocytes from hypothyroid patients or rats are variable: the rate of glucose utilization is reported to be normal, decreased or increased [17][18][19]. The effects of insulin on glucose utilization in skeletal muscle have been investigated in only one study: markedly decreased rates of glycolysis and glycogen synthesis in soleus muscles isolated from hypothyroid rats were reported [19]. However, these experiments were performed in the presence of supraphysiological concentrations of insulin. The glycogen content is increased in soleus muscles isolated from hypothyroid rats [20,21] and it is normal in skeletal muscle of hypothyroid patients [22,23] which does not suggest that hypothyroidism should markedly decrease the sensitivity of the rate of this process to insulin. In view of the variability of the results in the above studies, it was decided to investigate the sensitivity of glucose u...

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Regulation of lipogenesis in adipocytes independent effects of thyroid hormones, cyclic AMP and insulin on the uptake of deoxy-d-glucose

Cited by 15 publications

References 29 publications

Insulin Action in Adipose Tissue and Muscle in Hypothyroidism

Insulin Action in Adipose Tissue and Muscle in Hypothyroidism

Effect of Thyroid Status on Insulin Action in Rat Adipocytes and Skeletal Muscle

Effects of hypothyroidism on the sensitivity of glycolysis and glycogen synthesis to insulin in the soleus muscle of the rat

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