IMMUNOLOCALIZATION OF CALCITRIOL RECEPTOR, PLASMA-MEMBRANE CALCIUM-PUMP AND CALBINDIN-D-28K IN THE CORNEA AND CILIARY BODY OF THE RAT EYE

Epitopes of the calcitriol receptor, the ATP-dependent plasma membrane calcium pump (PMCA) and the 28-kD vitamin-D-dependent Ca-binding prot ein (calbindin-D-28k) were detected in sections of the albino rat eye using light microscopy and immunohistochemistry of paraffin-embedded t issues. Calcitriol receptor and calbindin-D-28k epitopes were detected in both the inner and outer layers of the ciliary body epithelium. PM CA was present in both epithelial cell layers of the ciliary body but was most prominent in the inner layer. Corneal epithelium and endothel ium also contained epitopes for calcitriol receptor, PMCA and calbindi n-D-28k. These Ca-regulatory proteins may play a role in the cellular physiology of the albino rat eye by maintaining appropriate intracellu lar and aqueous humor Ca concentrations.