Yes, it looks like there is very little turnover in adipocytes. They can,however, be induced to die.
I did a search on apoptosis (programmed cell death) and adipocytes and found an interesting review article:
Quote:
Targeted apoptosis of adipocytes
De novo differentiation of adipocytes from precursor cells is virtually irreversible. One of the reasons for the slow or non-existing turnover is the adipocyte's remarkable resistance to apoptosis [21]. The underlying mechanisms for the hardiness of this cell type are not clear, but can be explained in part by the very high Akt/protein kinase B levels in mature adipocytes. Furthermore, the levels of the anti-apoptotic factors Bcl-2 and neuronal apoptosis-inhibitory protein increase during adipogenesis, imparting resistance to cell death [22 and 23]. Caloric restriction leads to reduction of fat mass, but it does not necessarily involve a reduction of the number of fat cells. However, conditions of pathological fat wasting can involve loss of adipocytes through apoptotic mechanisms. For example, apoptotic events were observed in fat tissue of patients with tumor cachexia. Apoptosis was also implicated in the fat remodeling processes associated with highly active antiretroviral therapy in HIV infected patients with lipodystrophy [24, 25, 26 and 27]. Targeted and moderate induction of apoptosis in adipocytes could be an attractive approach to reduce the number of fat cells, particularly when coupled with a reduction of caloric intake to avoid spill over of lipids into other tissues. However, at this time little is known about the apoptotic machinery in adipocytes and thus therapeutic modalities relying on a selective induction of apoptosis within this cell type remain a distant prospect.
That would be pretty neat. Liposuction in a pill.
Taken from:
Quote:
1: Drug Discov Today. 2005 Sep 15;10(18):1219-30.
*
Keynote review: the adipocyte as a drug discovery target.
Nawrocki AR, Scherer PE.
Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA.
The adipocyte has pleiotropic functions beyond the storage of energy in times of nutrient abundance. Considerable efforts in adipocyte biology within the past ten years have emphasized the important role of adipose tissue in processes as diverse as energy metabolism, inflammation and cancer. Adipocytes are able to communicate with the brain and peripheral tissues implementing metabolic signals such as satiety, food intake and energy expenditure. Despite its huge pharmacological potential, only a small number of clinical applications interfere directly with adipocyte physiology. Here, we want to highlight various areas of adipocyte physiology that have not yet been explored pharmacologically and emphasize some of the limitations associated with these pharmacotherapies.
So our fat talks to our brain. Interesting.
They've been worried lately though, the supply line is drying up.
