I know this seems really basic, but is something I've always been unclear of. I always hear that insulin is like a key that lets glucose into your cells to be used as energy. So; if you take too much insulin, your cells suddenly suck too much of the sugar out of your blood, causing hypoglycemia. Why are your cells able to absorb more glucose than they need? And what do they use said energy for? What do the cells do with the excess glucose? It just disappears?
And the insulin prevents the fat from being broken back down into glucose. Thanks, Sally. Makes sense. I can't believe I never figured this part out.
So insulin certainly enables the uptake of glucose into our cells, but it also acts as a signaling hormone. When your dietary sources of glucose run low, the normal non-diabetic will lower their insulin levels and raise their glucagon levels to signal the liver to produce glucose (gluconeogenesis). When your insulin levels are too high, you actually suppress this glucose production further causing hypos. This same effect occurs with alcohol which is metabolized by our livers, gluconeogenesis is suppressed and we can suffer a hypo.
And Sally is right, fat burning (ketosis) is suppressed with higher insulin levels. But during ketosis fat is converted to ketone bodies (by our livers) and our cells actually burn ketones rather than glucose.
I've never been really confused by the hypo thing, what has always confused me is my son. He sits there, eats 250g of carbs in a sitting, has presumably normal blood sugar and insulin levels, yet he gains no weight. Where does all that glucose go? It can't go into his cells, we only store some 300 g of glycogen and he is a couch potato. And he doesn't convert it to bodyfat, he is rail thin. And we only excrete glucose when our blood sugar gets high (> 180 mg/dl), which he doesn't have. Where does it go? That is what I want to know.
I always figured there was a superstructural, brain component to hypos, like your brain gets fried as the main cause of the symptoms, figuring that since brains are convoluted and cooking away all the time, they need more blood/ energy/ etc. than the rest of us.
As everybody else mentioned, the excess glucose is converted into fat/glycogen for future use. Insulin is an anabolic hormone. When you have excess amounts of insulin and ATP, glycogenesis is promoted through positive feedback.
His basal metabolism rate is higher than average for some reason?
I know a few people like this. My only explanation is that the cells are using this energy. It could be for brain activity, or maybe he's just fidgeting or doing something invisible that demands energy. Maybe his body temperature is slightly elevated.
Sam hello we chatted once in the room this is a article i think you can follow about why insulin and hypoglycemia synthesize so much i hope its not to technical for you and if you need any questions answering i will very happy to.Its a excerlent paper
As to hypoglycemia shock i have come across it twice when i had to perfrom a autopsys.We also call it Dead in Bed Syndrome,Many who become Hypounware brain can programme to ignore the condtion and that is dangerouse also use HMG-CoA reductase inhibitors,thiazide diuretics,calcium channel blockers ETc ETC can also cause this to happen,cerebral arteriosclerosis is another condtion that can also cause this and is common once we pass 60 years of age,I can thinks of another 20 condtions.
Hyperthyroidism increases your metabolism rate. People with hypothyroidism tend to fidget and usually have higher than average temperature. Anybody see a connection here?
Not at all. I keep medical articles for my pleasure reading. Thank you! This one'll have to wait though seeing as I have a midterm on saturday.
I have a 3 yr old who was born premature, and is chronically underweight. He dropped for 20 to 3rd percentile on the growth chart after he quit breastfeeding. I test his BG periodically. He's always normal. Has his thyroid tested twice, along with full battery of tests. All normal. He is very strong, active and otherwise seems fine.
Well, this may be part of it. Clearly our metabolism slows as we age. And there are differences between individuals in terms of metabolism rate, but the differences are more like 25-30%. Still far from enough to explain the discrepancy.
Its his hormones its called growing up
Thanks for the link, Mishi. It is a very good read, although, I found the part on incretin particularly difficult.
Something that I am unclear on: Once energy needs are met, and glycogen stores are full; remainders are used to synthesize fat stores + triglycerides. So, fat would store a lot of energy. But when we eat fat, only 10% available as glucose. Why is this?
The simple answer is that glucose enters the cells through passive diffusion. As long as there is a higher concentration of glucose outside the cell, in the blood and interstitial fluid, compared to inside the cell's cytoplasm, when insulin opens the glucose dooors, glucose will continue to move into the cell.
It doesn't matter if the blood glucose concenration is a normal 80 mg/dl or a hypoglycemic 40 mg/dl. As long as cells continue to use glucose through the various pathways mentioned, there will always be a lower concentration of glucose inside the cell compared to outside the cell, so as long as there is insulin present to keep the doors open, glucose will enter the cell.
Actually, I don't think fat is converted to glucose at all unless we are in dire straits.
The glycerol in the triglycerides can be, but I haven't seen anything conclusive regarding the fatty acid portion once they've been liberated. I always understood the answer to that question to be no, no metabolic pathway in mammals exists.