THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Active transport is the key to the reabsorptive processes in the proximal tubule. Glucose and amino acids are reabsorbed across the apical membrane of the proximal tubule by sodium-coupled secondary active transport. Na+ glucose transport is mediated by the low affinity, high capacity SGLUT2 transport protein.

Detailed explanation-2: -The epithelial cells of renal tubule reabsorb these substances either by active or passive mechanisms. Substances like glucose, amino acids, Na+, are reabsorbed by active transport.

Detailed explanation-3: -As outlined in the following sections, glucose is taken up from the tubular fluid in the proximal tubule by two Na+-glucose cotransporters, SGLT2 and SGLT1, which are expressed in the brush border membrane of the early and later proximal tubule, respectively. Na+-glucose cotransport is a saturable process.