[quote]Fletch1986 wrote:
someone who can eat whatever he wants all day all week, do no cardio and still be lean and have muscle definition.[/quote]
I hate you now.
I’m not really sure why I bothered to type all of the following out since some people refuse to believe anything other than omggg fat slobs! but whatever…
Research in mice has shown that mice can become obese as a result of mutations in certain genes, with at least 5 that have now been identified - obese (ob), tubby (tub), fat (fat), diabetes (db). When you have a homozygous mutant it will eat excessively and have low energy expenditure, resulting in it becoming fat. Researchers then decided to use parabiosis to determine if these mutations caused changes that were hormone mediated. (parabiosis is when 2 animals are joined together, sutured at the pelvis, shoulder, and abdominal walls, the skin is joined and most importantly capillaries form between the 2 circulatory networks so the 2 animals share the circulatory network)
Mice produce a satiation or â??stop eatingâ?? hormone, however, the db/db mice lack the receptor reguired for the hormone to affect target cells. So, as db/db mice got fatter and fatter, they would produce more and more of the hormone with no effect. Now, the normal mouse that is joined to the db/db mouse is getting higher and higher levels of the hormone, and it cuts food intake, even though the mouse its joined to doesnâ??t.
The satiation hormone itself is encoded by the obese gene, and reduces appetitie and increases activity in response to increases in fatness. BUT the ob/ob mice donâ??t produce the hormone. They do have the receptors for it however so they can respond to the signal if its available from a parabiotic partner.
As some of you probably guessed by now that obese genes productâ?¦.leptin
So if you administer leptin to ob/ob mice, it will correct their obesity, however it still would have no effect on db/db mice because they donâ??t have the receptor for leptin.
Leptinâ??s main target is in the hypothalamus: 2 groups of neurons in the arcuate nucleus with opposing actions and energy homeostasis depends on balance between their actions
Orexigenic neurons: neuropeptide Y (NPY) and agouti-related peptide (AgRP) are colocalized
Anorexigenic neurons: prepro-opiomelanocortin (POMC) releases �±-melanocyte-stimulating hormone (�±MSH)
Low leptin levels - leptin binds to both groups of neurons, in response to low levels of leptin, you are activating orexigenic neurons, so you have high levels of NPY and AgRP, and low activity of aMSH. This signals the body to increase food intake
High leptin levels â?? anorexigenic neurons secrete POMC and aMSH, while secreting low levels of NPY and AgRP which will tell your body to stop eating.
the picture pretty much summarizes what i just said about the parabiotic research in mice.
[quote]Derek542 wrote:
[quote]Fletch1986 wrote:
someone who can eat whatever he wants all day all week, do no cardio and still be lean and have muscle definition.[/quote]
I hate you now. [/quote]
hataz gonna hate lol
[quote]relentless2120 wrote:
parabiosis…
[/quote]
Makes me think of this:
[quote]Fletch1986 wrote:
[quote]Derek542 wrote:
[quote]Fletch1986 wrote:
someone who can eat whatever he wants all day all week, do no cardio and still be lean and have muscle definition.[/quote]
I hate you now. [/quote]
hataz gonna hate lol[/quote]
[quote]Test Icicle wrote:
[quote]relentless2120 wrote:
parabiosis…
[/quote]
Makes me think of this:
[/quote]
lol had to go there huh