Editing Adipocyte (section)

== Structure ==
===White fat cells===
[[File:Brown fat cell.jpg|thumb|224x224px|A 
brown fat cell.]]
[[File: Yellow adipose tissue in paraffin section - lipids washed out.jpg|thumb|Yellow adipose tissue in paraffin.]]
White fat cells contain a single large [[lipid droplet]] surrounded by a layer of
[[cytoplasm]], and are known as unilocular. The [[Cell nucleus|nucleus]] is flattened and pushed to the periphery. A typical fat cell is 0.1&nbsp;mm in diameter<ref name=":1">{{cite journal | vauthors = Ye RZ, Richard G, Gévry N, Tchernof A, Carpentier AC | title = Fat Cell Size: Measurement Methods, Pathophysiological Origins, and Relationships With Metabolic Dysregulations | journal = Endocrine Reviews | volume = 43 | issue = 1 | pages = 35–60 | date = January 2022 | pmid = 34100954 | pmc = 8755996 | doi = 10.1210/endrev/bnab018 }}</ref> with some being twice that size, and others half that size. However, these numerical estimates of fat cell size depend largely on the measurement method and the location of the adipose tissue.<ref name=":1" /> The fat stored is in a semi-liquid state, and is composed primarily of [[triglyceride]]s, and [[cholesteryl ester]]. White fat cells secrete many proteins acting as [[adipokine]]s such as [[resistin]], [[adiponectin]], [[leptin]] and [[apelin]]. An average human adult has 30 billion fat cells with a weight of 30&nbsp;lbs or 13.5&nbsp;kg. If a child or adolescent gains sufficient excess weight, fat cells may increase in absolute number until age twenty-four.<ref name = "Pool_2001" /> If an adult (who never was obese as a child or adolescent) gains excess weight, fat cells generally increase in size, not number, though there is some inconclusive evidence suggesting that the number of fat cells might also increase if the existing fat cells become large enough (as in particularly severe levels of obesity).<ref name = "Pool_2001" /> The number of fat cells is difficult to decrease through dietary intervention, though some evidence suggests that the number of fat cells can decrease if weight loss is maintained for a sufficiently long period of time (>1 year; though it is extremely difficult for people with larger and more numerous fat cells to maintain weight loss for that long a time).<ref name = "Pool_2001" />

A large meta-analysis has shown that white adipose tissue cell size is dependent on measurement methods, adipose tissue depots, age, and body mass index; for the same degree of obesity, increases in fat cell size were also associated with the dysregulations in glucose and  lipid metabolism.<ref name=":1" />

===Brown fat cells===

[[Brown adipose tissue|Brown fat cells]] are [[Polyhedron|polyhedral]] in shape. Brown fat is derived from dermatomyocyte cells. Unlike [[white fat]] cells, these cells have considerable cytoplasm, with several [[lipid]] droplets scattered throughout, and are known as multilocular cells. The nucleus is round and, although eccentrically located, it is not in the periphery of the cell. The brown color comes from the large quantity of [[mitochondria]]. Brown fat, also 
known as "baby fat," is used to generate heat.

===Marrow fat cells===
Marrow adipocytes are unilocular like white fat cells.  The [[marrow adipose tissue]] depot is poorly understood in terms of its physiologic function and relevance to bone health. Marrow adipose tissue expands in states of low bone density but additionally expands in the setting of obesity.<ref name=":0">{{cite journal | vauthors = Styner M, Pagnotti GM, McGrath C, Wu X, Sen B, Uzer G, Xie Z, Zong X, Styner MA, Rubin CT, Rubin J | display-authors = 6 | title = Exercise Decreases Marrow Adipose Tissue Through β-Oxidation in Obese Running Mice | journal = Journal of Bone and Mineral Research | volume = 32 | issue = 8 | pages = 1692–1702 | date = August 2017 | pmid = 28436105 | pmc = 5550355 | doi = 10.1002/jbmr.3159 }}</ref> Marrow adipose tissue response to exercise approximates that of [[white adipose tissue]].<ref name=":0" /><ref>{{cite journal | vauthors = Pagnotti GM, Styner M | title = Exercise Regulation of Marrow Adipose Tissue | journal = Frontiers in Endocrinology | volume = 7 | pages = 94 | date = 2016 | pmid = 27471493 | pmc = 4943947 | doi = 10.3389/fendo.2016.00094 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Styner M, Pagnotti GM, Galior K, Wu X, Thompson WR, Uzer G, Sen B, Xie Z, Horowitz MC, Styner MA, Rubin C, Rubin J | display-authors = 6 | title = Exercise Regulation of Marrow Fat in the Setting of PPARγ Agonist Treatment in Female C57BL/6 Mice | journal = Endocrinology | volume = 156 | issue = 8 | pages = 2753–2761 | date = August 2015 | pmid = 26052898 | pmc = 4511140 | doi = 10.1210/en.2015-1213 }}</ref><ref>{{cite journal | vauthors = Styner M, Thompson WR, Galior K, Uzer G, Wu X, Kadari S, Case N, Xie Z, Sen B, Romaine A, Pagnotti GM, Rubin CT, Styner MA, Horowitz MC, Rubin J | display-authors = 6 | title = Bone marrow fat accumulation accelerated by high fat diet is suppressed by exercise | journal = Bone | volume = 64 | pages = 39–46 | date = July 2014 | pmid = 24709686 | pmc = 4041821 | doi = 10.1016/j.bone.2014.03.044 }}</ref> Exercise reduces both adipocyte size as well as marrow adipose tissue volume, as quantified by [[MRI]] or [[X-ray microtomography|μCT imaging]] of bone stained with the lipid binder [[osmium]].