The co-localization of stanniocalcin protein, mRNA and kidney cell markers in the rat kidney

Abstract

Stanniocalcin (STC) is a glycoprotein hormone that was first discovered in fish and recently identified in mammals. STC immunoreactive (STCir) cells have been identified in rat kidney and there is also evidence that the hormone functions as a regulator of renal phosphate homeostasis. In the present study we have identified STCir cells and tubules in the rat kidney by correlative immunocytochemistry using antibodies to STC and specific antigenic markers (Tamm-Horsfall protein and anion exchanger-1). The cellular sites of STC gene expression were also identified by in situ hybridization. Correlative immunocytochemistry revealed that STCir was present in all proximal straight tubule cells, all cortical thick ascending limb cells, all distal convoluted tubule cells, and both principal and -intercalated cells of the collecting duct system. On the other hand, in situ hybridization revealed that the STC gene was expressed only in cortical and medullary collecting duct cells. This suggests either that STC is being sequestered by segments that do not express the gene (making them putative targets of the hormone), or that STC mRNA levels were simply too low in these other segments to be detected by in situ hybridization.

Stanniocalcin 1 (STC1) Protein and mRNA Are Developmentally Regulated During Embryonic Mouse Osteogenesis: the Potential of STC1 as an Autocrine/Paracrine Factor for Osteoblast Development and Bone Formation

“…However, in contrast to fish STC, which is expressed only in the specialized CS, human (Chang et al 1995;Olsen et al 1996) and mouse (Chang et al 1996;Varghese et al 1998) STC1 mRNA has been reported to be expressed in multiple tissues and rat STC1protein has been detected in a number of tissues by radioimmunoassay (De Niu et al 2000). In addition, cell localization of STC1 mRNA and/or protein has been studied in detail in specific segments of the kidney in humans (De Niu et al 1998), rats (Hadded et al 1996;Wong et al 1998;Worthington et al 1999), and mice (Yoshiko and Maeda 1998). There is growing evidence that STC1 is able to regulate calcium/phosphate homeostasis in mammals (Wagner et al 1997;Madsen et al 1998).…”

Stanniocalcin-1 in the subfornical organ inhibits the dipsogenic response to angiotensin II

“…Brains were removed and placed overnight in the fixative at 4°C. Brains were then gradually dehydrated through a series of alcohols and placed in xylene followed by paraffin wax (67). Serial, transverse sections (6 m) through the region of SFO were cut on a microtome, mounted on double-gelatinized microscope slides, and placed on a slide warmer.…”

“…Slides were rinsed, and endogenous peroxidase activity was inhibited by exposing the sections to a 1% H2O2 solution for 10 min. Sections were washed in PBS and allowed to incubate overnight at 22°C in primary polyclonal rabbit STC-1 antiserum (1:750 in PBS/0.3% Triton-X 100 and 4% normal goat serum) (59,67). The STC-1 antiserum employed was generated in rabbits against hSTC (59,67) and has previously been characterized for specificity (8,21,42).…”

“…Mammalian STC-1 is a disulfide-linked glycoprotein dimer of identical subunits (41), which is expressed in a variety of tissues, including heart, kidney, adipose tissue, skeletal muscle, lung, ovaries (18,24), and brain (67)(68)(69). STC-1 functions in the cells of these tissues to maintain calcium homeostasis (24,63).…”

“…The role of STC-1 within the SFO is not known, although it may function in modulating intracellular calcium concentrations within neurons, which could affect their excitability (17,(67)(68)(69). The SFO has been suggested to be one of the most important structures within the forebrain laminae terminalis in the regulation of electrolyte and body fluid homeostasis (1,3,7,12,13,25,31,36,37).…”