Final answer:
The proximal convoluted tubule (PCT) reabsorbs substances such as Na+, glucose, and amino acids. The correct effect of PCT transporters is the reabsorption of bicarbonate (HCO3-) to maintain acid-base balance.
Step-by-step explanation:
The effects of transporters in the proximal tubules of the nephron are crucial for maintaining body fluid homeostasis. In the proximal convoluted tubule (PCT), most reabsorption occurs, where substances required by the body such as calcium (Ca++), sodium (Na+), glucose, and amino acids are reabsorbed into the bloodstream.
This process includes the reabsorption of bicarbonate (HCO3-) to maintain acid-base balance, which is crucial for proper physiological function.
Among the options provided, reabsorption of bicarbonate (HCO3-) is the correct effect of the transporters in the proximal tubules. Sodium is reabsorbed actively here, not secreted. While urea, potassium, and hydrogen ions play a role in overall kidney function, in the PCT specifically, urea is partially reabsorbed, potassium is not directly involved in this question's context, and hydrogen ion secretion does not describe the primary activity of transporters in the proximal tubules concerning the given options.