What are the 3 substances which are reabsorbed from the nephron in the blood?

The main substance re-absorbed into the blood in the nephron are glucose, electrolytes (sodium, potassium, chloride)  and water.

Almost all the glucose is reabsorbed at the proximal tubule of the nephron. Sodium, potassium and chloride are reabsorbed  at the ascending loop of  Henle, and water is reabsorbed at the descending loop of Henle.

Other nutrients that are reabsorbed are  magnesium, phosphates, carboxylate, bicarbonate, amino acids, some urea, proteins and oligopeptides.

Reabsorption occurs in two steps namely active or passive extraction of sustances  from the fluid  in the tubules of the nephron, and into the interstitium , then transport of these substances from interstitium and into the bloodstream.