Is thirst an after-effect of pituitary tumor removal?

Yes. Because the normal pituitary gland is rarely clearly identified in surgery, and due to inflammation after surgery, release of the hormone ADH (vasopressin) by the pituitary is often disrupted. Adh, (vasopressin) or anti-diuretic hormone, permits the body to maintain appropriate fluid balance. A low ADH (vasopressin) level causes excess urination, and consequently, thirst. This is usually temporary, but may be a long-term issue.
If pituitary stalk . Injured, can result in loss of vasopressin, increases loss of fluids from kidnet- presents as thirst, to prevent dehydration.