Well written, Lockwood 
now let’s do a recap:
glucose enters the blood stream and the first place it would go would me the glycogen stores but only if they are not at 100%. Once the reach the 100% the rest ot the exess glycose that is still in the blood stream has only one choice - “go for fat” - or in other words - do be stored in the adipose tissue.
Here is where I don’t get it - you write about “storing glucose in the adipose tissue” and “the later utilization ot this glucose” but as far as I know - the adipose tissue ist a adipose tissiue because it consists of fat. Right? And actually glucose is not really stored there but the enrgy it carries is used for the production ot fatty acids. Please, tell me where am I wrong.
And how can actually glucose be derived from the adipose stores?
thanx
[quote]Lockwood wrote:
fjolnirg wrote:
I’ve been wondering a bit about the following biochemical/nutritional questions (minutiae). Can anyone help out? (Berardi, Cy Willson, Dave Barr or other gurus perhaps?)
1.Since insulin activates the glut-4 receptor in muscle and adipose tissue, what makes it preferable to shuttle glucose into muscle rather than fat cells after exercise, also, what makes it preferable to move amino acids into muscle following exercise rather than other tissues?
2.If glucagon is active during a fast and stimulates gluconeogenesis (think V-diet) does extra protein completely spare muscle protein brakedown, or is the muscle protein broken down and consequently regenerated because of the positive nitrogen balance?
First off, bravo…GREAT freakin’ questions!!!
Answers to both: Homeostatic Response
- That said, GLU will actually contribute to adipose stores, post-exercise, IF consumption exceeds expenditure.
The reason muscle receives preferential treatment has to do w/ the tight regulation your nervous system has placed on their being a fixed and ready supply of available GLU. In other words, GLU will first refuel the nervous system (about 50% of all glucose you consume goes to functions w/in your brain), and then your muscles and liver stores are refueled secondary to the former. Anything in excess of expenditure and recovery needs is modified and stored in adipose tissue to add to the “buffer” capacity of energy reserves.
Remember, glucose derived from adipose stores requires the expenditure of energy. Thus, for your body to first refuel adipose stores would be energetically disadvantageous…that pretty much goes against all of biological evolution.
- If I’m reading your question correctly, and assuming you’re not talking about a prolonged fast (i.e. you’re simply talking about a short-term fast, and not prolonged starvation), then you’re exactly correct… assuming that protein intake exceeds catabolism so that net protein values remain positive.
The HPA (hypothalamic-pituitary-adrenal) axis is awesome, isn’t it? When glucose stores fall below your body’s set-point, glucagon is released and triggers a catecholaminergic response, leading to the release of NE and especially EPI from the adrenals.
In doing so, insulin-mediated uptake of blood glucose is thwarted and insulin release is turned off so as to minimize glucose utilization. Your nervous system receiving preferential treatment. Gluconeogenesis and ketogenesis is activated until glucose stores are again brought back into its set-point. Hunger, however, may not subside due to the likely connection b/w maintaining both glucose and adipose stores…however, that’s another topic altogether.
hope that I’ve answered your questions…or, at least, not made an ass of myself
- c
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