I get asked about this a lot. Gluconeogenesis. The brain uses the equivalent of something like ~120 g glucose/d. During starvation, brain still uses glucose, but less (because ketosis) and a bit differently (less oxidation, more lactate release).

The brain and the obligatory glycolytic tissues always use at least some glucose.  During starvation, this glucose comes from gluconeogenesis.

The substrates for gluconeogenesis are primarily lactate, pyruvate & alanine, glycerol, propionate, and some amino acids (not leucine or lysine). The relative proportions change depending on #context, eg, the duration since your last meal, diet composition (keto, LF, etc.), etc.

Recommended textbook: Stipanuk or Gropper.

Gluconeogenesis basically only occurs in the liver and kidney, and maybe the small intestine. For more on renal gluconeogenesis, see HERE. Today, we will focus on liver and gluconeogenic substrates.

THE CORI CYCLE: Obligatory glycolytic tissues and skeletal muscle during exercise release a lot of lactate.  This lactate enters the blood and is taken up by the liver where it is made into glucose. This glucose then goes back to peripheral tissues, is converted back to lactate and we have a "cycle!"  The Cori cycle. And technically speaking, it doesn't add "new" glucose, just recycles it if you will. 

The carbon of liver-derived glucose is carrying energy to the other tissues (eg, skeleta muscle or obligatory glycolytic tissues), in this way the oxidation of fatty acids in the liver can transfer energy from fatty acids to do gluconeogenesis which allows cells without mitochondria to obtain that energy. 

Integrated intermediary metabolism.

That's all for now!

Check out my Patreon campaign! $5 a month for full access to all content. It's ad-free and you can cancel if it sucks :-)

Affiliate linksjoin Binance and get some cryptoassets or download Honeyminer and get some Bitcoins for free! And now you can mine Bitcoin from your Chromebook!

Still looking for a pair of hot blue blockers? Carbonshade and TrueDark are offering 15% off with the coupon code LAGAKOS and Spectra479 is offering 15% off HERE. If you have no idea what I’m talking about, read this then this.

20% off some delish stocks and broths from Kettle and Fire HERE

If you want the benefits of  ‘shrooms but don’t like eating them, Real Mushrooms makes great extracts. 10% off with coupon code LAGAKOS. I recommend Lion’s Mane for the brain and Reishi for everything else

Join with this link.

Start your OWN Patreon campaign!

calories proper