title: Activin B inhibits lipolysis in 3T3-L1 adipocytes.
abstract: Activin B, consisting of two inhibin betaB (INHBB) subunits, is a hormone known to affect gonadal function, reproduction and fetal development. We have reported that INHBB and activin B receptors are highly expressed in adipocytes suggesting that activin B may have local effects in adipose tissue. In this study, we investigate the effect of activin B on lipolysis, measured as release of non-esterified fatty acids and free glycerol. Recombinant activin B decreased lipolysis in a concentration-dependent manner and increased intracellular triglyceride content in 3T3-L1 adipocytes. siRNA-mediated knock-down of INHBB expression increased lipolysis, and this effect was abolished by addition of recombinant activin B. In line with its inhibitory effect on lipolysis, activin B caused a down regulation of the expression of adipose triglyceride lipase and hormone sensitive lipase, key genes involved in lipolysis. In summary, we suggest that activin B is a novel adipokine that inhibits lipolysis in a paracrine or autocrine manner.
authors.affiliation: Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, Gothenburg University, Sahlgrenska Center for Cardiovascular and Metabolic Research, Gothenburg, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Magnusson
authors.forename: Per-Arne
authors.initials: PA
authors.lastname: Svensson
authors.forename: Lena M S
authors.initials: LM
authors.lastname: Carlsson
authors.forename: Kajsa
authors.initials: K
authors.lastname: Sjöholm
mesh_terms: D041721:3T3-L1 Cells; D028341:Activins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D017667:Adipocytes / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D005990:Glycerol / Q000378:metabolism; D028322:Inhibin-beta Subunits / Q000235:genetics / Q000502:physiology; D008066:Lipolysis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D051379:Mice; D034741:RNA, Small Interfering / Q000235:genetics; D014280:Triglycerides / Q000378:metabolism
chemical_list: D005230:Fatty Acids, Nonesterified; D034741:RNA, Small Interfering; D014280:Triglycerides; C044147:activin B; D028341:Activins; D028322:Inhibin-beta Subunits; D005990:Glycerol