Chapter category: Cell Metabolism
Development of White Adipose Tissue and Adipocyte Differentiation
Adipose Tissue
Edited by: Susanne KlausISBN: 1-58706-040-X
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Chapter authors:
Gérard Ailhaud
In humans, the development of white adipose tissue (WAT) occurs to a large extent postnatally and continues throughout life, in contrast to the development of brown adipose tissue (BAT) which takes place mainly before birth and disappears thereafter. The acquisition of fat cells appears to be an irreversible process, as apoptosis has not been shown to be significant under physiological conditions. At the cellular level, this phenomenon raises the question of the characteristics of the cells constituting the adipose tissue organ. This leads in turn to the question of the nature of the factors that regulate the formation of new fat cells from dormant adipose precursor cells. Once adipose tissue is formed, adipocytes represent between onethird and twothirds of the total number of cells. The remaining cells are blood cells, endothelial cells, pericytes, adipose precursor cells of varying degree of differentiation, and, most likely, fibroblasts. However, when studying WAT, the most provocative question which comes to mind when one considers the physiopathological consequences of overweight and obesity epidemic in developed and developing countries is "do we need WAT for normal life?" Part of the answer comes from evolution as, among invertebrates, adipose tissue represents an important organ in insects whereas its quantitative importance decreases in arachnids, crustaceans, and mollusks in which liver appears as a new organ. Among vertebrates, adipose tissue develops extensively in homeotherms, although its proportion of body weight can vary greatly between species (up to 40% of body weight in cetaceans) or within a species as it is the case in migrating birds and hibernating animals. But the most straightforward answer comes from the recent generation of transgenic mice largely devoid of WAT (vide infra: see below). The KO mice exhibit anatomical and physiological properties very similar to patients suffering from congenital generalized lipodystrophy which is characterized by severely decreased fat mass, hypertriglyceridemia and nonketotic diabetes. It is now realized that WAT is an endocrine organ which secretes leptin in proportion to its mass. As leptin is known among many effects to stimulate the gonadal axis and to promote reproductive functions WAT, which represents the main energy storage organ in the body, has become a major player in connecting reproduction and energy requirements.
Additional chapters from this book:
Adipose Tissue Pathology in Human Obesity
Hans Hauner, Thomas Skurk
Human obesity is characterized by an excess of adipose tissue mass that has potential adverse health consequences and may finally result in a reduced quality of life and life expectancy.
White Adipose Tissue as a Secretory and Endocrine Organ:Leptin and Other Secreted Proteins
Paul Trayhurn, Nigel Hoggard, D. Vernon Rayner
We are currently undergoing a revolution in our perspectives on the physiological role of white adipose tissue (WAT). Traditionally, white fat has been viewed primarily as a longterm energy...
Heterogeneity of Adipose Tissue Metabolism
Michael Boschmann
Adipose tissue is a highly specialized organ dealing mainly with processes for storage and release of energy. The underlying metabolic routes of these processes are regulated by a complex netw...
Central Nervous System Innervation of White Adipose Tissue
Timothy J. Bartness, Gregory E. Demas, C. Kay Song
The incessant demand for energy by tissues, especially the central nervous system (CNS), is a challenge that must be met for normal physiological functioning and behavior to occur. This is an ...
Central Nervous System Innervation of Brown Adipose Tissue
Timothy J. Bartness, C. Kay Song, Gregory E. Demas
Environmental factors such as ambient temperature and food availability can affect the survival and reproductive success of animals. This is especially important for small rodents with their i...
Brown Adipocyte Differentiation and Function in Energy Metabolism
Susanne Klaus
Brown adipose tissue (BAT) is a specialized thermogenic adipose tissue with greatimportance for thermoregulation and cold defense of small mammals. As outlined in the previous chapter, the ...
Brown Adipose Tissue: Thermogenic Function and Its Physiological
Susanne Klaus
Brown adipose tissue (BAT) is a specialized form of adipose tissue whose function is opposite to classical white fat function. As a thermogenic tissue it is a site of energy dis...
Development of White Adipose Tissue and Adipocyte Differentiation
Gérard Ailhaud
In humans, the development of white adipose tissue (WAT) occurs to a large extent postnatally and continues throughout life, in contrast to the development of brown adipose tissue (BAT) which ...
Morphology of the Adipose Organ
Saverio Cinti
The white adipose tissue is composed of spherical cells with a diameter ranging from 15 to 150 µm (Fig. 2) in aldehyde-fixed and paraffin or resin embedded specimens.
This enormou...
Overview: Biological Significance of Fat and Adipose Tissues
Susanne Klaus
From a human point of view fat or adipose tissue is nowadays often considered assuperfluous and undesired, especially considering the current "emaciated" beauty ideal of the Western world. Thi...
Development of White Adipose Tissue and Adipocyte Differentiation
Gérard Ailhaud
In humans, the development of white adipose tissue (WAT) occurs to a large extent postnatally and continues throughout life, in contrast to the development of brown adipose tissue (BAT) which ...
Morphology of the Adipose Organ
Saverio Cinti
The adipose organ (Fig. 1) of mammals is composed of two different tissues: white and brown adipose tissues.13 In mammals these tissues are organized in disti...
Overview: Biological Significance of Fat and Adipose Tissues
Susanne Klaus
From a human point of view fat or adipose tissue is nowadays often considered assuperfluous and undesired, especially considering the current "emaciated" beauty ideal of the Western world. Thi...
