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- Title
Altered insulin secretion associated with reduced lipolytic efficiency in aP2-/- mice.
- Authors
Scheja, Ludger; Makowski, Liza; Uysal, K. Teoman; Wiesbrock, Sarah M.; Shimshek, Derya R.; Meyers, Daniel S.; Morgan, Maureen; Parker, Rex A.; Hotamisligil, Gokhan S.; Scheja, L; Makowski, L; Uysal, K T; Wiesbrock, S M; Shimshek, D R; Meyers, D S; Morgan, M; Parker, R A; Hotamisligil, G S
- Abstract
Recent studies have shown that genetic deficiency of the adipocyte fatty acid-binding protein (aP2) results in minor alterations of plasma lipids and adipocyte development but provides significant protection from dietary obesity-induced hyperinsulinemia and insulin resistance. To identify potential mechanisms responsible for this phenotype, we examined lipolysis and insulin secretion in aP2-/- mice. Beta-adrenergic stimulation resulted in a blunted rise of blood glycerol levels in aP2-/- compared with aP2+/+ mice, suggesting diminished lipolysis in aP2-/- adipocytes. Confirming this, primary adipocytes isolated from aP2-/- mice showed attenuated glycerol and free fatty acid (FFA) release in response to dibutyryl cAMP. The decreased lipolytic response seen in the aP2-/- mice was not associated with altered expression levels of hormone-sensitive lipase or perilipin. The acute insulin secretory response to beta-adrenergic stimulation was also profoundly suppressed in aP2-/- mice despite comparable total concentrations and only minor changes in the composition of systemic FFAs. To address whether levels of specific fatty acids are different in aP2-/- mice, the plasma FFA profile after beta-adrenergic stimulation was determined. Significant reduction in both stearic and cis-11-eicoseneic acids and an increase in palmitoleic acid were observed. The response of aP2-/- mice to other insulin secretagogues such as arginine and glyburide was similar to that of aP2+/+ mice, arguing against generally impaired function of pancreatic beta-cells. Finally, no aP2 expression was detected in isolated pancreatic islet cells. These results provide support for the existence of an adipo-pancreatic axis, the proper action of which relies on the presence of aP2. Consequently, aP2's role in the pathogenesis of type 2 diabetes might involve regulation of both hyperinsulinemia and insulin resistance through its impact on both lipolysis and insulin secretion.
- Subjects
FATTY acid-binding proteins; PROTEIN deficiency; LIPOLYSIS; INSULIN; SECRETION; PROTEIN metabolism; ADIPOSE tissues; ANIMAL experimentation; BETA adrenoceptors; CARRIER proteins; CELL culture; CELL receptors; COMPARATIVE studies; FAT cells; FATTY acids; GENES; GENETIC disorders; LIPID metabolism disorders; RESEARCH methodology; MEDICAL cooperation; MICE; NERVE tissue proteins; PROTEINS; RESEARCH; RESEARCH funding; EVALUATION research
- Publication
Diabetes, 1999, Vol 48, Issue 10, p1987
- ISSN
0012-1797
- Publication type
journal article
- DOI
10.2337/diabetes.48.10.1987