<prompt> In renal glycosuria, the renal threshold for glucoseLowHighSameGreatly increased  <response>: A i.e., LowTranspo Maximum T.For most substance that are actively reabsorbed or secreted there is a maximum rate at which the solute can be transpoedQ ofter ka transpo maximum. This limit is dt saturation of specific transpo system.Tm for kidney in practice is less than calculated value i.e.,threshold of substance is less than its Tm because, not all nephrons have the same Tm and some of the nephron excrete substance before others have reached their TmQ. It is impoant to know that overall Tm of substance for kidney is reached when all nephrons have reached their capacity to reabsorb or secrete that substance.Tm for glucose in normal adult is - 375 mgminQ, whereas its filtered load is only 125mgmin GFR x Plasma glucose 125 mlmin x 1 mgml. With large increase in plasma glucose or GFR, which increase the filtered load above 375 mgmin, the excess glucose filtered is not reabsorbed passes into urine. However, even when the plasma glucose concentration rises above 200 mg100m1 2mgm1 so filtered load is 250 mgmin, which is less than Tm, a small amount of glucose appears in urine. This is known as threshold of glucose. So renal threshold of substance is the plasma level at which it first appears in urine in more than the normal minute volumes.Substances that do not exhibit Tm Substances that are passively reabsorbed do not demonstrate Tm, because their rate is determined by electrochemical gradient, permeability, time that solute remains within tubule eg. are urea, chlorideQ, water Some actively transpoed substance also have electrochemical gradient- time transpo. e.g. is Na reabsorption in PCTQ. However in DCT where epithelium has much tighter junction so transpoing only small amounts of Na sodium reabsorption exhibits Tm. 