Calcitriol the biologically active metabolite of vitamin D3 functions primarily through interaction with the intracellular vitamin D receptor (VDR) regulating transcription of genes involved in mineral homeostasis and immune responses It modulates cellular differentiation proliferation and adaptive immune functions via nuclear receptor-mediated mechanisms In vitro studies demonstrate that calcitriol dose-dependently inhibits lipopolysaccharide (LPS)-stimulated tumor necrosis factor-alpha (TNF- ) and interleukin-1 (IL-1 ) secretion from human peripheral blood mononuclear cells (PBMCs) Additionally animal models indicate that calcitriol administration decreases cytokine release associated with inflammatory stimuli through intracellular calcium-dependent signaling pathways Calcitriol is widely utilized in biomedical research concerning osteometabolic regulation immune modulation and cytokine signaling networks