Seocalcitol

Seocalcitol is a vitamin D analog, binds vitamin D receptor protein from human osteosarcoma MG-63 cells with K_d of 0.27 nM. IC50 & Target:Kd: 0.27 nM (vitamin D receptor)^[1] In Vitro:Seocalcitol (EB 1089) is a stimulators of osteoclast recruitment in murine bone marrow cultures, with EC₅₀ at 0.1 nM. Seocalcitol stimulates bone resorption with an estimated EC₅₀ at 0.03 nM^[1]. Seocalcitol (EB 1089) elicites a dose-dependent induction of 24-hydroxylase mRNA in the kidney (EC₅₀=0.4±0.13). In the kidney, K_d values for Seocalcitol is 0.48±0.04 nM. However, in the intestine, the K_d for Seocalcitol is 1.43±0.19 nM)^[2]. Seocalcitol (0.1-10 nM) induces cell differentiation in a dosedependent manner. A higher differentiating activity is observed for 1 nM Seocalcitol (EB 1089) than for 1 nM VD₃. In Vivo:Seocalcitol (EB1089), a synthetic vitamin D analog, exhibits reduced hypercalcemic activity relative to 1,25(OH)₂VD₃. In another study, long-term intraperitoneal (IP) administration of Seocalcitol at a dose of 0.5 μg/kg body weight every other day in C3H/Sy mice exertes a very strong inhibitory effect on hepatocellular carcinoma (HCC) development^[4]. Seocalcitol (EB 1089) is administered daily to postnatal rats from 4 to 12 days of age (P4 to P12) by intraperitoneal injection at either 0.38 or 1.25 μg/kg body weight (BW)/day. Only the highest dose of Seocalcitol (1.25 μg/kg BW) causes a significant reduction in weight gain when administered alone or in conjunction with Dexamethasone, all-trans retinoic acid (RA), or retinoic acid^[5].