{"id":1733,"date":"2020-08-14T17:32:47","date_gmt":"2020-08-14T17:32:47","guid":{"rendered":"https:\/\/meddists.com\/learn\/pre-clinical\/biochemistry\/biochemistry-of-the-metabolism\/carbohydrate-metabolism\/regulatory-mechanisms-in-glucose-getabolism-and-gluconeogenesis\/"},"modified":"2021-10-17T18:03:59","modified_gmt":"2021-10-17T16:03:59","slug":"regulatory-mechanisms-in-glucose-getabolism-and-gluconeogenesis","status":"publish","type":"page","link":"https:\/\/meddists.com\/learn\/pre-clinical\/biochemistry\/biochemistry-of-the-metabolism\/carbohydrate-metabolism\/regulatory-mechanisms-in-glucose-getabolism-and-gluconeogenesis\/","title":{"rendered":"Regulatory mechanisms in glucose metabolism I."},"content":{"rendered":"\n

The regulation of the pathways can be done by:<\/p>\n\n\n\n
  1. allosteric small molecules (ATP, ADP, cAMP, NADH, NAD+<\/sup>)<\/li>
  2. end products of the reaction<\/li>
  3. calcium or magnesium<\/li>
  4. hormones<\/li><\/ol>\n\n\n\n

    <\/div><\/p>\n\n\n\n

    Modulating hormones \u2014 Glucagon & Adrenaline<\/h2>\n<\/span>\n\n\n
    \"\"<\/a>
    Figure 1. Hormonal regulation of the liver -cAMP pathway<\/strong><\/figcaption><\/figure><\/div>\n\n\n\n

    Glucagon<\/strong> or Adrenaline<\/strong> binds to the membrane of hepatocytes, which regulates (stimulates or inhibits) certain enzymes through the cAMP pathway<\/strong> (Figure 1).<\/p>\n\n\n\n

    While the kinases are inactivating the glycogen synthase<\/strong>, they activate the glycogen phosphorylase<\/strong>.

    The generated glucose-1-p<\/strong> is transported via the bloodstream to the peripheral tissues, later it is used in glycolysis.<\/p>\n\n\n<\/span>\n

    Fructose-2,6-bisphosphate <\/h2>\n<\/span>\n\n\n
    \"\"<\/a>
    Figure 2. PFK I & II – production of F-2,6 BP<\/strong><\/figcaption><\/figure><\/div>\n\n\n\n

    This molecule is derived from fructose-6-phosphate by the action of phosphofructokinase II<\/em>.<\/p>\n\n\n\n

    PFK II is working in the presence of insulin.<\/p>\n\n\n\n

    When fructose-2,6-bisphosphate is present it: Increases the rate of glycolysis<\/strong>.

    It decreases gluconeogenesis<\/strong> (by activating phosphofructokinase I)<\/p>\n\n\n<\/span>\n

    Modulation of the Glycolysis and Gluconeogenesis<\/h2>\n<\/span>\n\n\n
    \"\"<\/a>
    Figure 3. Effects of insulin<\/strong><\/figcaption><\/figure><\/div>\n\n\n\n

    In the case of the Insulin from the F-6-P, the body is producing the F-1,6 BP<\/strong>. However, due to the insulin strong glycolytic supportive effect, the PFK II will be activated<\/strong> too (Figure 3).<\/p>\n\n\n\n

    PFK II together with the insulin<\/strong> is producing the F-2,6 BP<\/strong>, which is a positive allosteric activator of the PFK I.<\/strong> <\/p>\n\n\n\n

    F-2,6 BP activated PFK I is making more F-1,6 BP<\/strong> and the glycolytic pathway is enhanced, initiated from the insulin effect.<\/p>\n\n\n\n

    \"\"<\/a>
    Figure 4. Effects of glucagon<\/strong><\/figcaption><\/figure><\/div>\n\n\n\n

    In the case of the Glucagon from the F-1,6-BP, the body is producing the F-6 P<\/strong>. However, due to the Glucagone strong gluconeogenic supportive effect, the FBPase II will be activated<\/strong> too (Figure 4). <\/p>\n\n\n\n

    FBPase II<\/strong> together with the glucagon<\/strong> is producing the F-6 P<\/strong>, which is a positive allosteric activator of the FBPase.<\/strong> <\/p>\n\n\n\n

    F-1,6 BP activated FBPase is making more F-6 P<\/strong> and the gluconeogenic pathway is enhanced, initiated from the glucagon effect. <\/p>\n\n\n<\/span>\n

    Modulating hormones \u2014 Insulin<\/strong><\/h2>\n<\/span>\n\n\n

    Insulin is likely to induce cAMP to AMP conversion<\/strong> due to cyclic nucleotide phosphodiesterase. Its effect is opposite to glucagon.<\/p>\n\n\n\n

    In the liver:<\/p>\n\n\n\n