Multisubject doubts

[Pathinterpreter]

Please, can somebody explain any of this?

1. What's the relation of height and sex hormones? (Why klinefelter is tall and Turner is little?)
2. ATP produced by glucose. So till now I know: in glycolisis - 8 (with malate shunt); pyruvate to acetyl CoA - 6; TCA cycle - 24... Why 8, 6? What about the ATP's consumed in glycolisis? Does each glucose produces 2 glucose 6-P?
3. Somebody please explain Tertiary hyperparathyroidism.

Thanks in advance.


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The best runner is the one that ignores is in a race.

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[mercaptovizadeh]

Please, can somebody explain any of this?

1. What's the relation of height and sex hormones? (Why klinefelter is tall and Turner is little?)
2. ATP produced by glucose. So till now I know: in glycolisis - 8 (with malate shunt); pyruvate to acetyl CoA - 6; TCA cycle - 24... Why 8, 6? What about the ATP's consumed in glycolisis? Does each glucose produces 2 glucose 6-P?
3. Somebody please explain Tertiary hyperparathyroidism.

Thanks in advance.


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The best runner is the one that ignores is in a race.

1.) Not sure about whether this is correct or not, but estrogen together with somatomedin from the liver drives long bone growth. Testosterone closes the epiphyseal plates. A Klinefelter person has more estrogen and less androgen than a typical male and perhaps more growth hormone and IGF-1 (somatomedin C) than a female, so the long bones have longer to elongate. A Turner's person may have lower levels of GH and estrogen and so does not have the stimulus for bone elongation. These are all my suppositions, though.

2.) What do you mean by 8, 6? 36 are produced using the glycerol-3-phospate shuttle, since you use two NADH in the cytosol (i.e. 6 ATP equivalents) to make 2 FADH2 in the mitochondrion (i.e. 4 ATP equivalents), so you've lost 2 net ATP. The malate shuttle keeps transfers electrons from NADH in the cytosol to NAD+ in the mitochondrion, so you keep all 6 ATP. So, 24 (TCA cycle) + 6 (pyruvate dehydrogenase) + 6/8 (glycolysis) = 36/38. About the ATP of glycolysis, you actually make 4 ATP but you use up 2 ATP so you gain net 2 ATP. 2 ATP are made in the phosphoglycerate kinase step and 2 ATP in the pyruvate kinase step. Subtract the 1 ATP used by glucokinase/hexokinase step and the 1 ATP used by the phosphofructokinase step and you get 2 net ATP from glycolysis (and 2 NADH from the glyceraldehyde phosphate dehydrogenase step).

3.) This arises after you've tried to treat secondary hyperparaythyroidism with a drug such as cinacalcet. It's essentially refractory secondary hyperparathyroidism. I don't know that it's known what causes it, but I suppose that it might be analogous to the prostate overcoming the effects of finasteride - perhaps mutations occur in PTH gland tissue such that it overcomes the effect of the drug?

 

[Pathinterpreter]

Ook, Thank you very much. But still don't understand about ATP production. Why does the 12 ATP produced in TCA cycle have to be multiplied by 2? Does each glucose produce 2 acetyl CoA (I think it does, but do not know how..). Thanks in advance.

 

[Fuzuli]

1. What's the relation of height and sex hormones? (Why klinefelter is tall and Turner is little?)

Clinical features of Turner syndrome is related with the haploinsufficiency of SHOX (short stature homeobox) gene , which is located on the X chromosome. SHOX gene affects epiphyseal bone growth.
Number of SHOX copies in Klinefelter's syndrome causes the tall stature.

2. ATP produced by glucose. So till now I know: in glycolisis - 8 (with malate shunt); pyruvate to acetyl CoA - 6; TCA cycle - 24... Why 8, 6? What about the ATP's consumed in glycolisis? Does each glucose produces 2 glucose 6-P?

• Up to fructose-1,6-bisphosphate (FBP), 2 ATP is used per glucose [-2 ATP]
• Each FBP molecule is broken down to glyceraldehyde 3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP) by aldolase enzyme.
• DHAP is converted into G3P by triose phosphate isomarase, thus from one FBP molecule, the yield is 2 G3P molecules
• From G3P, up to the synthesis of pyruvate, 1 NADH and 2 ATP molecules are produced per G3P. Since there are 2 G3P molecules for each glucose (1 NADH + 2 ATP) x 2 = 2 NADH + 4 ATP
• So, 2 NADH + 4 ATP - 2 ATP = 2 NADH + 2 ATP are synthesized per glycose per glycolysis cycle.
• Since each NADH yields 3 ATPs in TCA cycle, total amount of ATP comes down to 6 ATP + 2 ATP = 8 ATP

3. Somebody please explain Tertiary hyperparathyroidism.

• Primary hyperparathyroidism: Due to excessive PTH secretion, which is usually caused by adenoma of the parathyroid gland
• Secondary hyperparathyroidism: Due to the response of parathyroid glands to levels of hypocalcemia, which is usually caused by vit. D deficiency (renal failure) and decreased calcium intake
• Tertiary hyperparathyroidism: After prolonged hypocalcemia, parathyroid gland gains autonomity and begins to secrete excessive amounts of PTH.

For instance, a patient develops renal failure. As a result, vit D deficiency develops and hypocalcemia occurs. As a response to hypocalcemia, parathyroid glands start to secrete more PTH. If renal failure is prolonged, hypocalcemia persists, which acts as a continuous stimulant for PTH secretion. Due to this persistent stimulation, parathyroid gland gains autonomy and starts to secrete excessive amounts of PTH. This is called as tertiary hyperparathyroidism.