Cell size and the antilipolytic effect of insulin in human subcutaneous adipose tissue

Östman, Jan; Bäckman, Lars; Hallberg, D

doi:10.1007/bf00429841

Cited by 29 publications

(9 citation statements)

References 20 publications

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“…Our study does not support this hypothesis, since the lipolytic activity in absence of insulin is even higher in virgin than in the 7-day pregnant rats but the antilipolytic effect of insulin is ϳ30% higher in the latter group. Others have found a positive correlation between the antilipolytic effect of insulin and the size of human fat cells (44). However, we do not find such a relationship in our study, so differences in fat cell size cannot explain this higher response in the 7-day pregnant rat.…”

Section: Discussioncontrasting

confidence: 98%

Fat accumulation in the rat during early pregnancy is modulated by enhanced insulin responsiveness

Ramos

Crespo-Solans

Campo

et al. 2003

American Journal of Physiology-Endocrinology and Metabolism

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Insulin sensitivity has been implicated in the variation of fat accumulation in early gestation by as-yet-unknown mechanisms. In the present study, we analyzed the insulin sensitivity of lipolysis and lipogenesis in lumbar adipocytes from rats at 0, 7, 14, and 20 days of gestation. In adipocytes of 7-day pregnant rats, we found a twofold decrease in both β-agonist (isoproterenol and BRL-37344)-stimulated lipolysis and β3-adrenoceptor protein but not in lipolysis initiated by forskolin or isobutylmethylxanthine, suggesting a modification of the lipolytic pathway at the receptor level. Whereas adipocytes from 7-day pregnant rats showed a twofold increase in fatty acid synthesis from glucose, those from 20-day pregnant animals displayed a decreased lipogenic activity. Insulin responsiveness of the lipolytic and lipogenic pathways was analyzed by dose-response experiments, giving evidence for the involvement of improved insulin responsiveness in the enhanced lipogenic and reduced lipolytic activities of adipocytes in early pregnancy. In contrast, insulin resistance is responsible for lower antilipolytic and lipogenic actions of insulin in late pregnant animals. In conclusion, the present study shows that enhanced adipose tissue insulin responsiveness during early pregnancy contributes to maternal fat accumulation, whereas decreased insulin responsiveness during late gestation modulates fat breakdown.

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Section: Discussioncontrasting

confidence: 98%

Fat accumulation in the rat during early pregnancy is modulated by enhanced insulin responsiveness

Ramos

Crespo-Solans

Campo

et al. 2003

American Journal of Physiology-Endocrinology and Metabolism

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show abstract

“…Nonetheless, several important observations have been made. In general, basal lipolysis correlates positively with fat cell size (11,30,36), so that larger adipocytes have greater basal lipolytic activity per cell. This may explain why some investigators find regional differences in basal adipocyte lipolysis and others fail to.…”

Section: Basal Lipolysismentioning

confidence: 96%

LIPOLYSIS:Contribution from Regional Fat

Jensen

1997

Annu. Rev. Nutr.

135

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In vitro studies of adipocytes taken from different body fat regions suggest substantial differences in lipolysis between intra-abdominal, lower-body subcutaneous, and abdominal subcutaneous regions. Gender and obesity appear to influence these regional differences. In situ measurements of glycerol release from adipose tissue provided further evidence that regional heterogeneity of lipolysis occurs in humans. In vivo studies of regional free fatty acid (FFA) release have confirmed that adipose tissue lipolysis varies between upper- and lower-body fat. Release of FFA from lower-body adipose tissue is less than that from upper-body adipose tissue in both obese and non-obese men and women. In non-obese men and women, meal ingestion suppresses FFA release from all adipose tissue regions, and adrenergic stimulation activated FFA release from different sites in a gender-specific fashion. Significant regional and gender differences in adipose tissue lipolysis occur in humans, and this could contribute to differences in the health effects of adipose tissue and could theoretically influence body fat distribution.

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“…4). Basal lipolysis is related to adipocyte size in vitro, and the increased adipocyte size encountered in obese patients is probably responsible for the increased lipolysis and plasma free-fatty acid concentrations (60,61). In addition, although hypothetical, obese patients may have a decreased sensitivity to the inhibition of muscu- Both plasma glucose and plasma insulin concentrations after oral glucose were decreased markedly by weight loss.…”

Section: Effects Of Insuun Resistance On Carbohydrate and Lipid Metabmentioning

confidence: 99%

Energy and Substrate Metabolism in Obesity and Postobese State

Tappy

Felber²,

Jéquier³

1991

Diabetes Care

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The total energy expenditure (EE) of human beings is represented by basal metabolic rate (which corresponds to 60-70% of EE), dietary-induced thermogenesis (10% of EE), and the energy expended in physical activity (20-30% of EE). Obese individuals have an increased total EE compared with lean subjects; this increase is essentially due to an increased lean body mass concomitant with obesity, and is completely reverted after weight loss. Glucose-induced thermogenesis (GIT), measured during an oral glucose tolerance test (OGTT) or hyperinsulinemic-euglycemic clamps, has been found to be decreased in obese individuals, although some discrepancy exists between studies. The observed decreases in GIT show a gradation, increasing progressively from obese patients with normal glucose tolerance to obese patients with impaired glucose tolerance (IGT) to obese patients with non-insulin-dependent diabetes mellitus (NIDDM) and an increased insulin response after OGTT to obese patients with NIDDM and a hypoinsulinemic response after OGTT. The defect in GIT appears to be related to impairment in nonoxidative glucose storage and with the degree of insulin resistance. Obese patients after weight loss show a further decrease in GIT after OGTT or during a euglycemic clamp, which remains unclear. Obese patients have an increased basal lipid oxidation and a decreased suppression of lipid oxidation after OGTT or during a euglycemic clamp. Glucose oxidation and storage are both markedly decreased during a euglycemic clamp. In contrast, the defect in glucose storage is less apparent after OGTT, due to the compensatory effect of hyperglycemia and hyperinsulinemia.(ABSTRACT TRUNCATED AT 250 WORDS)

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Cell size and the antilipolytic effect of insulin in human subcutaneous adipose tissue

Cited by 29 publications

References 20 publications

Fat accumulation in the rat during early pregnancy is modulated by enhanced insulin responsiveness

Fat accumulation in the rat during early pregnancy is modulated by enhanced insulin responsiveness

LIPOLYSIS:Contribution from Regional Fat

Energy and Substrate Metabolism in Obesity and Postobese State

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