In a healthy individual, which of these substances would you expect to be present in the tubular fluid entering the loop of Henle?

Na+, glucose and urea are present in the initial filtrate formed. Nearly all the essential nutrients (e.g. glucose) are reabsorbed in the PCT and hence glucose doesn’t enter the loop of Henle. About 70-80% of Na+ is reabsorbed in the PCT. Some urea is reabsorbed from the medullary collecting ducts to maintain desired osmolarity. So, Na+ and urea will be present in the filtrate that enters the loop of Henle.