Male osteoblasts respond more robustly to 1α,25(OH)
than females, an effect enhanced on microstructured titanium (Ti). Confluent cultures of rat calvarial osteoblasts were plated on Ti surfaces and treated with 1α,25(OH)2D3. Cell number (A, B), alkaline phosphatase specific activity in cell lysates (C, D) and osteocalcin in the conditioned media (E, F) were measured after 24 hour treatment with either vehicle, 10-9M 1α,25(OH)2D3 or 10-8M 1α,25(OH)2D3. *P < 0.05, Ti surfaces versus tissue culture polystyrene at each concentration; #P < 0.05, 1α,25(OH)2D3 versus control; black circle, P < 0.05, 10-9M 1α,25(OH)2D3 versus 10-8M.