Fill in the Blanks kidneyOnline version fill in the gaps by Natalie Hodgson 1 ADH gland dilute more urine little less ADH high blood The kidneys produce urine if there is too much water in the blood or concentrated urine if there is too water in the blood . If the water content of the blood is too low , the pituitary releases a hormone called into the . This causes the kidneys to re - absorb water and results in a more concentrated urine . If the water content of the blood is too , less is released into the blood water is re - absorbed in the kidneys resulting in a more dilute .