This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid and Parathyroid, Subject name: Pathology
PTH does not cause: 
Select and explain. 
A. Maintains serum Ca2+, B. Ca2+ retention, C. Decreased PO43- excretion, D. May cause osteolysis
C: Decreased PO43- excretion
Answer: C: Decreased PO43- excretion 
Explanation: Ans. is 'c' decreased P043- excretionParathyroid hormone decreases the reabsorption of P043- in proximal convoluted tubule of kidney. This increases their excretion from the kidney.Effect of parathyroid hormoneon calcium*it increases serum calcium level byStimulates reabsorption of Ca by kidneyStimulates renal activation of vit. D which increases intestinal absorption of calciumOn Phosphorus*Decrease the level of P043- in Serum byDecreasing P043- reabsorption in kidney.