Adipose tissue endocrine functions

Additional roles traditionally recognised for white adipose tissue include thermal insulation (as in the blubber of sea mammals) and mechanical protection to internal organs. However, in recent years it has become apparent that the function of white adipose tissue is much more extensive. This follows from the discovery that it is a major endocrine organ, secreting a diverse... 

Figure 17.20 Cytokines produced by activated Th cells and some of their effects. The cytokines produced have several functions activation of B-cells, macrophages and cytotoxic T-cells. The cytokines, along with endocrine hormones, stimulate responses in the whole body (e.g. lipolysis in adipose tissue, protein degradation in muscle, acute phase protein production in liver. Chapter 18).

The ovary normally ceases its gametogenic and endocrine function with time. This change is accompanied by a cessation in uterine bleeding (menopause) and occurs at a mean age of 52 years in the USA. Although the ovary ceases to secrete estrogen, significant levels of estrogen persist in many women as a result of conversion of adrenal and ovarian steroids such as androstenedione to estrone and estradiol in adipose and possibly other nonendocrine tissues. 

Most POPs are readily absorbed (via the digestive system and inhalation) and accumulate in fatty tissue, including brain and adipose tissue and human milk. These substances can induce neurological effects and cause altered functioning of the nervous system as well as acting as endocrine disruptors. 

P-lipotropic hormone lipotropin. lipotropin ( 5-lipotropic hormone LPH) is a linear peptide with 90 amino acid residues, p-lipotropin itself contains the sequences of y-lipotropin (a less potent lipotropic hormone), P-melanotropin (P-MSH), [Met ] enkephalin and P-endorphin. It is an anterior pituitary hormone derived from propiomelanocortin, and has endocrine functions. P-lipotropin stimulates the release of fatty acids from adipose tissue. There is a high degree of sequence homology... 

Fig. 43.6. Effects of epinephrine on fuel metabolism and pancreatic endocrine function. Epinephrine (Epi) stimulates glycogen breakdown in muscle and liver, gluconeogenesis in liver, and lipolysis in adipose tissue. Epinephrine further reinforces these effects because it increases the secretion of glucagon, a hormone that shares many of the same effects as epinephrine. Epi also inhibits insulin release but stimulates glucagon release from the pancreas.

Furthermore we have proposed the concept that the adipose tissue in addition to its endocrine function acts as a reservoir for many lipophilic liposoluble exogenous carcinogens and that these carcinogens can be permanently released in the blood circulation and target peripheral tissues for carcinogenesis. [3, 4],... 

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