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

Abstract

in the subfornical organ inhibits the dipsogenic response to angiotensin II. Am J Physiol Regul Integr Comp Physiol 303: R921-R928, 2012. First published August 29, 2012 doi:10.1152 doi:10. /ajpregu.00057.2012 for the calcium-regulating glycoprotein hormone stanniocalcin-1 (STC-1) have been found within subfornical organ (SFO), a central structure involved in the regulation of electrolyte and body fluid homeostasis. However, whether SFO neurons produce STC-1 and how STC-1 may function in fluid homeostasis are not known. Two series of experiments were done in Sprague-Dawley rats to investigate whether STC-1 is expressed within SFO and whether it exerts an effect on water intake. In the first series, experiments were done to determine whether STC-1 was expressed within cells in SFO using immunohistochemistry, and whether protein and gene expression for STC-1 existed in SFO using Western blot and quantitative RT-PCR, respectively. Cells containing STC-1 immunoreactivity were found throughout the rostrocaudal extent of SFO. STC-1 protein expression within SFO was confirmed with Western blot, and SFO was also found to express STC-1 mRNA. In the second series, microinjections (200 nl) of STC-1, ANG II, a combination of the two or the vehicle were made into SFO in conscious, unrestrained rats. Water intake was measured at 0700 for a 1-h period after each injection in animals. Microinjections of STC-1 (17.6 or 176 nM) alone had no effect on water intake compared with controls. However, STC-1 not only attenuated the drinking responses to ANG II for about 30 min, but also decreased the total water intake over the 1-h period. These data suggest that STC-1 within the SFO may act in a paracrine/autocrine manner to modulate the neuronal responses to blood-borne ANG II. These findings also provide the first direct evidence of a physiological role for STC-1 in central regulation of body fluid homeostasis. body fluid homeostasis; thirst; circumventricular organs; calciumregulating glycoprotein STANNIOCALCIN (STC) IS A GLYCOPROTEIN hormone first identified and characterized within bony fish corpuscles of Stannius, endocrine glands derived from renal tubular cells (18,24,29,63,64). These glands are thought to produce and release STC into the circulation in response to rising serum calcium levels (11,18,29,64). The STC then acts on the gills and gut epithelial cells to reduce calcium uptake, while STC within the kidney causes increases in reabsorption of phosphate (11,18,24), a mechanism that likely aids in chelating excess extracellular calcium (18,24). The net effect of these STC actions is the restoration of serum calcium levels (14,18,24,62).A mammalian homolog of STC has been identified that shares a 73% amino acid sequence homology with fish STC (41). 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 (67-69). STC-1 functions in the cells of these tissues ...

Predictors of Thirst in Intensive Care Unit Patients

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Angiotensin II Type 1a Receptors in the Subfornical Organ Modulate Neuroinflammation in the Hypothalamic Paraventricular Nucleus in Heart Failure Rats

“…SFO microinjection was performed as previously described (Moreau et al, 2012; Wei et al, 2015). Briefly, rats were anesthetized (ketamine 100 mg/kg + xylazine 10 mg/kg IP) and positioned in a stereotaxic apparatus (Kopf Instruments; Tujunga, CA, USA).…”

Stanniocalcin 1 effects on the renal gluconeogenesis pathway in rat and fish

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