Kidney threshold

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The kidney threshold is the maximum re- absorption capacity of the kidneys for a certain substance (e.g. glucose). Glucose is first freely filtered into the primary urine in the kidney . In the further course, under normal conditions, glucose is reabsorbed by the kidneys from the primary urine, so that no glucose is contained in the urine of healthy individuals.

Only when the blood sugar rises above approx. 180 mg / dl (corresponds to 10 mmol / l) in humans , for example in the case of diabetes mellitus , glucose can no longer be completely reabsorbed and passes into the urine ( glucosuria ). This fact is also reflected in the name diabetes mellitus (“honey-sweet flow”). In domestic dogs , the kidney threshold is also 180 mg / dl, while in domestic cats it is significantly higher at over 250 mg / dl (> 13.8 mmol / l).

The blood sugar concentration at which sugar begins to be excreted in the urine is called the kidney threshold. It is different for every person and can change in the course of life. So she is z. B. lower in pregnancy and in children, while it increases in old age. Drugs can also affect the kidney threshold.

Individual evidence

  1. ^ Joachim Rassow: Biochemistry. 2nd updated edition. Georg Thieme, Stuttgart 2008, ISBN 978-3-13-125352-1 , p. 268.
  2. Astrid Wehner, Sylvia Geist: Update on insulin therapy in dogs and cats. In: Small Animal Practice. Vol. 59, No. 8, 2014, pp. 443-462, doi : 10.2377 / 0023-2076-59-443 .