PMID- 8194485
OWN - NLM
STAT- MEDLINE
DCOM- 19940628
LR  - 20071115
IS  - 0013-7227 (Print)
IS  - 0013-7227 (Linking)
VI  - 134
IP  - 6
DP  - 1994 Jun
TI  - Tumor necrosis factor increases the rate of lipolysis in primary cultures of 
      adipocytes without altering levels of hormone-sensitive lipase.
PG  - 2581-8
AB  - To investigate the effects of cytokines on adipocyte lipolysis, a macrophage cell 
      line (RAW 264.7) was treated with Escherichia coli lipopolysaccharide (1 
      microgram/ml) for 18 h to induce cytokine release. Conditioned medium (5%, 
      vol/vol) from these cells was added to rat epididymal adipocytes isolated and 
      incubated under sterile conditions. After incubation, the adipocytes were washed, 
      and the rate of lipolysis (glycerol release) was determined after a further 1-h 
      incubation. The conditioned medium caused an approximately 2.7-fold increase in 
      lipolysis, detectable after 6-12 h, maximal by 24 h, and reversible by 48 h after 
      washing the cells. The effect of conditioned medium was reversed by a 
      neutralizing antibody to mouse tumor necrosis factor-alpha (TNF alpha), and the 
      direct addition of recombinant human TNF alpha (0.1-50 ng/ml) reproduced the 
      effect, with a half-maximally effective concentration of approximately 3 ng/ml. 
      The effect of TNF on the expression of hormone-sensitive lipase (HSL; the 
      rate-limiting enzyme for lipolysis) was investigated by Western immunoblots using 
      an antibody raised to a bacterially expressed 96-amino acid portion of the HSL 
      enzyme. TNF treatment did not alter the concentration of immunoreactive HSL. From 
      these data we conclude that 1) macrophages release a cytokine(s) in response to 
      lipopolysaccharide that stimulates lipolysis in freshly isolated adipocytes; 2) 
      TNF alpha can account for most, or perhaps all, of this effect; 3) TNF alpha 
      increases the rate of lipolysis by a mechanism that does not involve increased 
      expression of HSL. Based on the time-dependent aspects of TNF alpha stimulation 
      and the lack of change in immunoreactive HSL, the findings suggest a TNF-induced 
      posttranslational modification of the enzyme.
FAU - Green, A
AU  - Green A
AD  - Department of Internal Medicine, University of Texas Medical Branch, Galveston 
      77555.
FAU - Dobias, S B
AU  - Dobias SB
FAU - Walters, D J
AU  - Walters DJ
FAU - Brasier, A R
AU  - Brasier AR
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Endocrinology
JT  - Endocrinology
JID - 0375040
RN  - 0 (Culture Media, Conditioned)
RN  - 0 (Lipopolysaccharides)
RN  - 0 (Recombinant Proteins)
RN  - 0 (Tumor Necrosis Factor-alpha)
RN  - EC 1.1.1.27 (L-Lactate Dehydrogenase)
RN  - EC 3.1.1.13 (Sterol Esterase)
SB  - IM
MH  - Adipocytes/*metabolism
MH  - Animals
MH  - Base Sequence
MH  - Cells, Cultured
MH  - Culture Media, Conditioned
MH  - Escherichia coli
MH  - Immunosorbent Techniques
MH  - Kinetics
MH  - L-Lactate Dehydrogenase/metabolism
MH  - *Lipolysis
MH  - Lipopolysaccharides/pharmacology
MH  - Macrophages/metabolism
MH  - Male
MH  - Mice
MH  - Molecular Sequence Data
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Recombinant Proteins/pharmacology
MH  - Sterol Esterase/*metabolism
MH  - Tumor Necrosis Factor-alpha/*pharmacology
EDAT- 1994/06/01 00:00
MHDA- 1994/06/01 00:01
CRDT- 1994/06/01 00:00
PHST- 1994/06/01 00:00 [pubmed]
PHST- 1994/06/01 00:01 [medline]
PHST- 1994/06/01 00:00 [entrez]
AID - 10.1210/endo.134.6.8194485 [doi]
PST - ppublish
SO  - Endocrinology. 1994 Jun;134(6):2581-8. doi: 10.1210/endo.134.6.8194485.