Quantitative electron microscopy shows uniform incorporation of triglycerides into existing lipid droplets.
Histochem Cell Biol
; 132(3): 281-91, 2009 Sep.
Article
en En
| MEDLINE
| ID: mdl-19557427
ABSTRACT
The lipid droplet (LD) is an organelle with a lipid ester core and a surface phospholipid monolayer. The mechanism of LD biogenesis is not well understood. The present study aimed to elucidate the LD growth process, for which we developed a new electron microscopic method that quantifies the proportion of existing and newly synthesized triglycerides in individual LDs. Our method takes advantage of the reactivity of unsaturated fatty acids and osmium tetroxide, which imparts LDs an electron density that reflects fatty acid composition. With this method, existing triglyceride-rich LDs in 3Y1 fibroblasts were observed to incorporate newly synthesized triglycerides at a highly uniform rate. This uniformity and its persistence even after microtubules were depolymerized suggest that triglycerides in fibroblasts are synthesized in the local vicinity of individual LDs and then incorporated. In contrast, LDs in 3T3-L1 adipocytes showed heterogeneity in the rate at which lipid esters were incorporated, indicating different mechanisms of LD growth in fibroblasts and adipocytes.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Triglicéridos
/
Metabolismo de los Lípidos
Límite:
Animals
Idioma:
En
Revista:
Histochem Cell Biol
Asunto de la revista:
CITOLOGIA
/
HISTOCITOQUIMICA
Año:
2009
Tipo del documento:
Article
País de afiliación:
Japón