Hormone-sensitive lipase, the rate-limiting enzyme in triglyceride hydrolysis, is expressed and active in beta-cells
Författare
Summary, in English
Triglycerides in the beta-cell may be important for stimulus-secretion coupling, through provision of a lipid-derived signal, and for pathogenetic events in NIDDM, where lipids may adversely affect beta-cell function. In adipose tissues, hormone-sensitive lipase (HSL) is rate-limiting in triglyceride hydrolysis. Here, we investigated whether this enzyme is also expressed and active in beta-cells. Northern blot analysis and reverse transcription-polymerase chain reaction demonstrated that HSL is expressed in rat islets and in the clonal beta-cell lines INS-1, RINm5F, and HIT-T15. Western blot analysis identified HSL in mouse and rat islets and the clonal beta-cells. In mouse and rat, immunocytochemistry showed a predominant occurrence of HSL in beta-cells, with a presumed cytoplasmic localization. Lipase activity in homogenates of the rodent islets and clonal beta-cells constituted 2.1 +/- 0.6% of that in adipocytes; this activity was immunoinhibited by use of antibodies to HSL. The established HSL expression and activity in beta-cells offer a mechanism whereby lipids are mobilized from intracellular stores. Because HSL in adipocytes is activated by cAMP-dependent protein kinase (PKA), PKA-regulated triglyceride hydrolysis in beta-cells may participate in the regulation of insulin secretion, possibly by providing a lipid-derived signal, e.g., long-chain acyl-CoA and diacylglycerol.
Avdelning/ar
Publiceringsår
1999
Språk
Engelska
Sidor
228-232
Publikation/Tidskrift/Serie
Diabetes
Volym
48
Issue
1
Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
American Diabetes Association Inc.
Ämne
- Endocrinology and Diabetes
Status
Published
Forskningsgrupp
- Insulin Signal Transduction
- Islet cell physiology
- Molecular Endocrinology
ISBN/ISSN/Övrigt
- ISSN: 1939-327X