Expression and localisation of stanniocalcin 1 in rat bladder, kidney and ovary

Bony fish use the glycoprotein hormone stanniocalcin (STC) to counteract hy percalcaemia. This is achieved through dual mechanisms involving gill calci um uptake inhibition and stimulation of renal inorganic phosphate reabsorpt ion. Human STC (hSTC-1) shows considerable homology with both rat and mouse STC (mSTC) and their mRNA is expressed in a wide range of tissues. In fish , STC is produced by endocrine glands known as the corpuscles of Stannius b ut in mammals the widespread expression is suggestive of a paracrine rather than an endocrine role. In order to determine the distribution and structu ral characteristics of hSTC-1, the recombinant protein was expressed in bac teria, purified by metal-ion affinity chromatography, and a study was made of the likely epitopes for raising an antibody. This novel hSTC-1 antibody was used to test the purification protocol. Since the role of mammalian STC is largely unknown, the specific distribution of STC needed to be addresse d. To test the specificity of the antibody, sodium dodecyl sulfate-polyacry lamide gel electrophoresis (SDS-PAGE)/Western blotting was undertaken in ho mogenised rat bladder, ovary and kidney.