Adipose Tissue Free Fatty Acid Storage In Vivo: Effects of Insulin Versus Niacin as a Control for Suppression of Lipolysis.

Insulin stimulates the translocation fatty acid transport protein 1 (FATP1) to plasma membrane, and thus greater free fatty acid (FFA) uptake, in adipocyte cell models. Whether insulin stimulates greater FFA clearance into adipose tissue in vivo is unknown. We tested this hypothesis by comparing direct FFA storage in subcutaneous adipose tissue during insulin versus niacin-medicated suppression of lipolysis.

Sexual dimorphisms in the associations of BMI and body fat with indices of pubertal development in girls and boys.

Context: The effect of obesity and concomitant insulin resistance on pubertal development is incompletely elucidated.

Objective: To determine how measures of adiposity and insulin resistance are associated with pubertal maturation in boys and girls.

Setting And Design: Breast and pubic hair Tanner stage and testicular volume by orchidometry were determined by physical examination in 1066 children.

Sex-associated differences in free fatty acid flux of obese adolescents.

Context: In obesity, increases in free fatty acid (FFA) flux can predict development of insulin resistance. Adult women release more FFA relative to resting energy expenditure (REE) and have greater FFA clearance rates than men. In adolescents, it is unknown whether sex differences in FFA flux occur.

Systemic free fatty acid disposal into very low-density lipoprotein triglycerides.

We measured the incorporation of systemic free fatty acids (FFA) into circulating very low-density lipoprotein triglycerides (VLDL-TGs) under postabsorptive, postprandial, and walking conditions in humans. Fifty-five men and 85 premenopausal women with BMI 18-24 (lean) and 27-36 kg/m(2) (overweight/obese) received an intravenous bolus injection of [1,1,2,3,3-(2)H5]glycerol (to measure VLDL-TG kinetics) and either [1-(14)C]palmitate or [9,10-(3)H]palmitate to determine the proportion of systemic FFA that is converted to VLDL-TG. Experiments started at 0630 h after a 12-h overnight fast.

Measuring plasma fatty acid oxidation with intravenous bolus injection of 3H- and 14C-fatty acid.

Accurate measures of plasma FA oxidation can improve our understanding of diseases characterized by impaired FA oxidation. We describe and compare the 24 h time-courses of FA oxidation using bolus injections of [1-(14)C]palmitate versus [9,10-(3)H]palmitate under postabsorptive, postprandial, and walking conditions. Fifty-one men and 95 premenopausal women participated in one condition (postabsorptive, postprandial, or walking), one tracer ((14)C- or (3)H-labeled), and an acetate or palmitate study.

Storage rates of circulating free fatty acid into adipose tissue during eating or walking in humans.

We measured subcutaneous adipose tissue free fatty acid (FFA) storage rates in postprandial and walking conditions to better understand the contributions of this pathway to body fat distribution. Palmitate tracers were infused intravenously and fat biopsies collected to measure palmitate storage in upper- (UBSQ) and lower-body subcutaneous (LBSQ) fat in 41 (17 men) and 40 (16 men) volunteers under postprandial and under postabsorptive walking conditions, respectively. Postprandial palmitate storage was greater in women than men in UBSQ (0.

Free fatty acid storage in human visceral and subcutaneous adipose tissue: role of adipocyte proteins.

Objective: Because direct adipose tissue free fatty acid (FFA) storage may contribute to body fat distribution, we measured FFA (palmitate) storage rates and fatty acid (FA) storage enzymes/proteins in omental and abdominal subcutaneous fat.

Research Design And Methods: Elective surgery patients received a bolus of [1-(14)C]palmitate followed by omental and abdominal subcutaneous fat biopsies to measure direct FFA storage. Long chain acyl-CoA synthetase (ACS) and diacylglycerol acyltransferase activities, CD36, fatty acid-binding protein, and fatty acid transport protein 1 were measured.

Storage of circulating free fatty acid in adipose tissue of postabsorptive humans: quantitative measures and implications for body fat distribution.

Objective: Preferential upper-body fat gain, a typical male pattern, is associated with a greater cardiometabolic risk. Regional differences in lipolysis and meal fat storage cannot explain sex differences in body fat distribution. We examined the potential role of the novel free fatty acid (FFA) storage pathway in determining body fat distribution in postabsorptive humans and whether adipocyte lipogenic proteins (CD36, acyl-CoA synthetases, and diacylglycerol acyltransferase) predict differences in FFA storage.

Links between mothers' and children's disinhibited eating and children's adiposity.

Few studies have examined relationships between parents' and children's specific disinhibited eating behaviors. We investigated links among mothers' and children's binge/loss of control eating, eating in the absence of hunger, and children's adiposity in 305 non-treatment-seeking youth, aged 8-17 years (13.62±2.

A novel ELISA for measuring CD36 protein in human adipose tissue.

CD36 is a transmembrane protein present in many tissues that is believed to facilitate inward fatty acid transport. Western blotting is the most widely used method to measure tissue CD36 protein content, but it is time consuming, technically demanding, and semiquantitative. To more precisely measure adipose tissue CD36 content we developed an enzyme linked immunosorbent assay (ELISA) after establishing that: 1) the anti-CD36 antibodies gave a single distinct band on traditional Western blots, and 2) the vast majority of adipocyte CD36 resides in the plasma membrane.

Acute effects of betahistine hydrochloride on food intake and appetite in obese women: a randomized, placebo-controlled trial.

Background: Central nervous system histaminergic tone is thought to play a role in appetite regulation. In animal models, histamine receptor 1 (HRH1) agonists and histamine receptor 3 (HRH3) antagonists decrease food intake.

Objective: The objective of this study was to examine the acute effects of betahistine hydrochloride (an HRH1 agonist and HRH3 antagonist) on food intakes and appetites.

Eating in the absence of hunger in adolescents: intake after a large-array meal compared with that after a standardized meal.

Background: Eating in the absence of hunger (EAH) is typically assessed by measuring youths' intake of palatable snack foods after a standard meal designed to reduce hunger. Because energy intake required to reach satiety varies among individuals, a standard meal may not ensure the absence of hunger among participants of all weight strata.

Objective: The objective of this study was to compare adolescents' EAH observed after access to a very large food array with EAH observed after a standardized meal.

Fatty acid metabolism in the elderly: effects of dehydroepiandrosterone and testosterone replacement in hormonally deficient men and women.

Context: Aging, low dehydroepiandrosterone (DHEA), and testosterone are associated with increased adiposity and metabolic risk. Treatment with these hormones may improve these abnormalities.

Objective: The objective of the study was to determine effects of aging, DHEA, or testosterone replacement on adiposity, meal fat partitioning, and postabsorptive lipolysis.