Histomorphometric effects of calcitonin on pharyngeal bone in fed and starved goldfish Carassius auratus

Abstract

The effects of salmon calcitonin (sCT) on osteoblasts and osteoclasts were histologically and histomorphometrically investigated in the pharyngeal bone of fed and starved goldfish Carassius auratus. The thickness of the osteoid and the height of osteoblasts were also measured. Fish were given sCT intraperitoneally at a dose of 10 ng/g bodyweight four times every other day under either fed or starved conditions. The sCT treatment induced the retraction of osteoclasts and their disengagement from the bone surface. Salmon calcitonin had no effect on the histomorphometric parameters of bone formation activity, but suppressed the parameter (OcP/EP) that showed osteoclast activity. Salmon calcitonin did not affect the thickness of the osteoid, but increased the height of osteoblasts in starved fish. Histological and histomorphometric results demonstrated that osteoclast activity was suppressed when sCT was given to starved estrogenized goldfish five times for 10 days. Overall, results suggest that calcitonin is involved in bone assimilation by suppressing osteoclast activity and by enhancing osteoblast activity in the pharyngeal bone of goldfish.