Lipolysis during fasting. Decreased suppression by insulin and increased stimulation by epinephrine.

Jensen, Michael D.; Haymond, Morey W.; Gerich, J. E.; Cryer, Philip E.; Miles, John M.

doi:10.1172/jci112785

Cited by 197 publications

(115 citation statements)

References 41 publications

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“…EPI, NE, and cortisol are not only all involved in the stress response, but all three hormones are also involved in inducing lipolysis. Increased lipid store availability is especially important in animals that undergo long-term fasting (Jensen et al, 1987;Rizack, 1961), with fatty acid oxidation providing energy and assisting in glucose-dependent tissue metabolic requirements (Houser et al, 2007). The catecholamine concentration increase across both types of fasts and the lack of a parallel cortisol concentration increase suggests a baseline concentration measurement as well as an important role of EPI and NE in fasting northern elephant seals.…”

Section: Discussionmentioning

confidence: 99%

Variation in adrenal and thyroid hormones with life-history stage in juvenile northern elephant seals (Mirounga angustirostris)

Jelincic

Tift

Houser

et al. 2017

General and Comparative Endocrinology

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Section: Discussionmentioning

confidence: 99%

Variation in adrenal and thyroid hormones with life-history stage in juvenile northern elephant seals (Mirounga angustirostris)

Jelincic

Tift

Houser

et al. 2017

General and Comparative Endocrinology

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“…Because these two fatty acids are the major fatty acids found in plasma, their metabolism can be taken to be representative of the bulk of plasma FFA. Both palmitate and oleate tracers were complexed to albumin before administration as previously described (19,20). Procedures common to both protocols Subjects.…”

Section: Methodsmentioning

confidence: 99%

Plasma Free Fatty Acid Storage in Subcutaneous and Visceral Adipose Tissue in Postabsorptive Women

et al. 2008

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1OBJECTIVE-We assessed the direct (VLDL-triglycerides [VLDL-TG] independent) storage of circulating free fatty acids (FFAs) in visceral and subcutaneous fat in postabsorptive women.RESEARCH DESIGN AND METHODS-Twelve women (BMI 29.6 Ϯ 6.6 kg/m 2 ) received an identical, intravenous bolus dose of [1-14 C]oleate followed by timed subcutaneous fat biopsies (abdominal and femoral) and then omental fat biopsy during tubal ligation surgery. Regional fat masses were assessed by combining dual-energy X-ray absorptiometry and computed tomography scanning. Separately, we assessed the fraction of FFA tracer entering VLDL-TG over the time representing the delay in collecting omental fat.RESULTS-Site-specific fat specific activity (SA) (dpm/g lipid) decreased as a function of fat mass in both upper-body subcutaneous (UBSQ) and visceral fat depots. These patterns are consistent with dilution of a relatively fixed amount of FFA tracer within progressively greater amounts of fat. Interestingly, femoral SA did not vary as a function of lower-body subcutaneous (LBSQ) fat mass. [1-14 C]oleate storage per million LBSQ adipocytes was positively associated with LBSQ fat mass, but no significant relationships were observed in UBSQ or visceral fat depot. The fraction of [1-14 C]oleate stored in UBSQ, LBSQ, and visceral fat was 6.7 Ϯ 3.2, 4.9 Ϯ 3.4, and 1.0 Ϯ 0.3%, respectively. Only ϳ4% of the tracer traversed VLDL-TG over 9.5 h. CONCLUSIONS-The increase in FFA tracer storage per adipocyte as a function of LBSQ fat mass implies that LBSQ adipocytes, in contrast to UBSQ and omental adipocytes, store more FFA in women with greater adiposity. The direct FFA storage pathway might play a role in favoring lower-body fat accumulation in women.

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“…Analyses. [9,10-3 H]palmitate (specific activity 60 Ci/mmol; American Radiolabeled Chemicals, St. Louis, MO) was prepared for infusion as previously described (13,14). Plasma palmitate specific activity was measured by highperformance liquid chromatography (13); [ 2 H 31 ]palmitate was used as an internal standard for determination of palmitate and total FFA concentrations (15).…”

Section: Methodsmentioning

confidence: 99%

Nocturnal and Postprandial Free Fatty Acid Kinetics in Normal and Type 2 Diabetic Subjects

et al. 2003

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Whether free fatty acid (FFA) rate of appearance (R a ) is increased in type 2 diabetes is controversial. To characterize nocturnal and postprandial abnormalities in FFA kinetics and to determine the effects of treatment with insulin sensitizers on lipolysis, we measured palmitate R a in control subjects (n ‫؍‬ 6) and individuals with poorly controlled, sulfonylurea-treated type 2 diabetes (HbA 1c ‫؍‬ 8.7 ؎ 0.2%, n ‫؍‬ 20), the latter before and at the end of 12 weeks of treatment with troglitazone (600 mg/day, n ‫؍‬ 4), metformin (ϳ2,000 mg/day, n ‫؍‬ 8), or placebo (n ‫؍‬ 8). Subjects consumed a standard breakfast at 0800 h. Results in control subjects and type 2 diabetic subjects were compared at baseline. Integrated nocturnal FFA R a (AUC 1:00 -8:00 A.M. ) was ϳ50% higher in type 2 diabetic subjects than in control subjects (29.4 ؎ 3.0 vs. 19.4 ؎ 3.9 mmol ⅐ m ؊2 ⅐ 7 h ؊1 , respectively, P < 0.05), whereas postprandial palmitate R a (AUC 0 -240 min ) was almost threefold higher in type 2 diabetic subjects than in control subjects (14.2 ؎ 1.7 vs. 5.3 ؎ 1.0 mmol ⅐ m ؊2 ⅐ 4 h ؊1 , respectively, P < 0.01). After troglitazone treatment, nocturnal palmitate R a did not change, but postprandial palmitate R a decreased by ϳ30% (P < 0.05). Palmitate kinetics did not change with metformin or placebo treatment. In summary, nocturnal and postprandial FFA R a is increased in type 2 diabetes. Postprandial lipolysis appears to be preferentially improved by thiazolidinediones compared with nocturnal lipolysis. Diabetes 52:675-681, 2003 P atients with type 2 diabetes have resistance to the antilipolytic effects of insulin on adipose tissue (1,2). This dysregulation of adipose tissue lipolysis has been implicated as a major cause of the abnormalities in lipoprotein and glucose metabolism that are characteristic of type 2 diabetes (3). However, plasma free fatty acid (FFA) turnover has been reported to be both increased (4) and normal (5-8) in type 2 diabetes.FFA tracer studies in patients with type 2 diabetes have generally been performed under postabsorptive conditions (4,5,7) or during a hyperinsulinemic-euglycemic clamp (1,2); little information is available regarding nocturnal and postprandial FFA metabolism. In fact, patients with poorly controlled type 2 diabetes exhibit an increase in plasma FFA concentrations during the night (9), but it is not known whether this is the result of increased release of FFA into the systemic circulation or decreased plasma FFA clearance. An understanding of fatty acid metabolism during nocturnal and absorptive conditions is important because postabsorptive measurements may not necessarily reflect conditions at other times of the day.The treatment of type 2 diabetes has been revolutionized by the availability of medications, including biguanides and thiazolidinediones, which improve insulin action on glucose metabolism. In addition, some (10,11) but not all (12) studies suggest that these agents may improve abnormalities in FFA metabolism in the postabsorptive state and during hyperinsulin...

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Lipolysis during fasting. Decreased suppression by insulin and increased stimulation by epinephrine.

Cited by 197 publications

References 41 publications

Variation in adrenal and thyroid hormones with life-history stage in juvenile northern elephant seals (Mirounga angustirostris)

Variation in adrenal and thyroid hormones with life-history stage in juvenile northern elephant seals (Mirounga angustirostris)

Plasma Free Fatty Acid Storage in Subcutaneous and Visceral Adipose Tissue in Postabsorptive Women

Nocturnal and Postprandial Free Fatty Acid Kinetics in Normal and Type 2 Diabetic Subjects

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