L calcium. Paratholluone also enhances renal excretion of phosphate Posphaturia -3 serum phosphate. Because of unavailability of calcium and phosphate, bone mineralization is decrease --> compensatory increase in osteoblastic activity --> Increase alkaline phosphatase. So, there isi) Normal to decreased calcium ii)   Decreased phosphate (except in renal osteodystrophy, where phosphate level is increased because kidney is not able to excrete calcium). iii) Increased parathormone iv) Increased alkaline phosphatase 2. Hypophosphatemic RicketsThis is due to deficiency of phosphate Decreased phosphate. Calcium level is normal. As there is no calcium deficiency, there is no compensatory hyperparathyroidism -> Normal paratlzornzone. Due to unavailability of phosphate, mineralization of bone is decreased and there is increase in compensatoryosteoblastic activity    ->    Alkaline phosphatase">