Histochemical studies of lysosomal forming system in osteoclasts with calcitonin treatment: Acid phosphatase and glucose-6-phosphatase

To evaluate whether calcitonin influences the lysosomal forming system in osteoclasts, acid phosphatase (ACPase) and glucose-6-phosphatase (G6Pase) were examined in cells with and without hormonal treatment. Many osteoclasts treated with calcitonin (CT) separated from or attached only partly to the bone surface, and the ruffled border (RE) disappeared. In ACPase activity, the reactive products of the enzyme were present in small and large lysosomes, Golgi apparatus, and on the membrane of the RE in CT-free (control) osteoclasts. The reactive products were also present in the same organelles of CT-treated osteoclasts, except RE, but the enzymal activity in the Golgi apparatus was lower than that in control osteoclasts. Additionally, the number of small lysosomes increased strikingly, In G6Pase activity, the reactive products of the enzyme were present in endoplasmic reticulum (ER), nuclear envelope, and vacuoles in CT-treated osteoclasts as well as in control osteoclasts, The vacuoles with the enzyme-positive were distinguished from the lysosomes in size, and the number increased remarkably in CT-treated osteoclasts. From these results, there is a possibility that calcitonin influences the function of Golgi apparatus in the lysosomal forming system of osteoclasts, resulting in the appearance of vacuoles with G6Pase activity.