Which part of the nephron is primarily responsible for glucose absorption?

The proximal convoluted tubule (PCT) is primarily responsible for glucose absorption in the nephron. Approximately 100% of the glucose that enters the nephron is reabsorbed here under normal physiological conditions. This process occurs through active transport mechanisms involving specific transport proteins, such as sodium-glucose cotransporters (SGLTs), which utilize the sodium gradient to transport glucose back into the bloodstream.

The PCT is highly specialized for reabsorption and not only absorbs glucose but also other substances including amino acids, bicarbonate, and a significant portion of the water and electrolytes that enter the filtrate. The structure of the PCT, with its microvilli, increases the surface area for absorption, making it efficient at reclaiming glucose before the filtrate moves further along the nephron.

In contrast, the other parts of the nephron, such as the descending and ascending loops of Henle and the distal convoluted tubule, are involved in different functions related to water and electrolyte reabsorption but do not play a significant role in glucose absorption.