Disease relevance of S100g

• Rats with short bowel syndrome had significantly lower mucosal concentrations of calbindin-D9K (P less than 0.001) and a parallel reduction of both intestinal calcium absorption (P less than 0.001) and p-1,25-dihydroxyvitamin D (P less than 0.01) in spite of a general hypertrophy of the duodenal mucosa [1].
• Vitamin D-deficient rats responded to dexamethasone treatment (100 micrograms/100 g of body weight/day for 4 days) with a 2.5-fold increase in intestinal VDR mRNA which was accompanied by a 4-fold decrease in intestinal calbindin-D9k mRNA [2].
• A model of pulmonary adenocarcinoma in transgenic mice expressing the simian virus 40 T antigen driven by the rat Calbindin-D9K (CaBP9K) promoter [3].
• Induction of hypertension in Dahl-S rats reduced intestinal calbindin-D9k and increased plasma levels of 1,25(OH)2 vitamin D, while renal calbindin-D28k levels, plasma calcium levels and plasma magnesium levels were unchanged [4].
• Calcium absorption and gene expression of calbindin-D9k were decreased in uremia and were also improved by phosphorus restriction [5].

High impact information on S100g

• Intestinal calcium-binding protein (calbindin-D9K) and renal calcium-binding protein (calbindin-D28K) levels were measured by enzyme-linked immunoadsorbent assays in rats with short bowel syndrome induced by resection of about 85% of the small intestine [1].
• Calbindin-D9k was quantified and its cellular location was defined in uterus, yolk sac, and placenta [6].
• Gestational changes in calbindin-D9k in rat uterus, yolk sac, and placenta: implications for maternal-fetal calcium transport and uterine muscle function [6].
• During early pregnancy (days 0-4), calbindin-D9k was present in the two smooth muscle layers [6].
• Progesterone appeared to be a good candidate for controlling the midgestational decrease of uterine muscle calbindin-D9k, as it blunted estrogen's induction of the protein in the muscle layers and stroma in a dose-dependent manner [6].

Chemical compound and disease context of S100g

• A single injection of 1,25-(OH)2D3 to uremic rats caused an increase in the steady-state calbindin-D9k mRNA level, and decreases in steady state c-fos and ODC mRNA levels, suggesting that the deficiency of 1,25-(OH)2D3 is responsible for intestinal dysfunction in uremia [5].
• The effects of calcitriol and a novel calcitriol analogue, 22-oxacalcitriol (OCT) on duodenal Ca transport, calbindin-D9k mRNA, and calbindin-D9k content were studied in two animal models reflecting common human pathologies, namely arterial hypertension and chronic renal failure, as well as in normal rats [7].

Biological context of S100g

• A calcium binding protein, calbindin-D9k, is mainly regulated by estrogen in the pituitary gland of rats during estrous cycle [8].
• Dynamic changes also occurred in the calbindin-D9k contents of the two layers of uterine smooth muscle (outer longitudinal and inner circular) during mid- and late gestation [6].
• The induction of calbindin-D9k in these cells coincided with the time of exponential fetal bone growth and maximal fetal accumulation of calcium, suggesting a role of the protein in these epithelial layers in maternal-fetal calcium transport [6].
• The present studies were undertaken to characterize the expression of calcium binding protein (CaBP or calbindin-D9k) in uterine tissues [9].
• However, the interhelical angle of helixes 3 and 4 in the normal EF-hand (Omega3-4 = 106 +/- 4 degrees) changed significantly upon the addition of Ca2+ (DeltaOmega3-4 = 112 +/- 5 degrees) and is similar to that of the Ca2+-bound EF-hands in calbindin D9K, calmodulin, and troponin (84 degrees </= Omega </= 128 degrees) [10].

Anatomical context of S100g

• Calcium-related proteins include the calcium transporters 1 and 2 (CaT1 and CaT2), plasma membrane Ca2+-ATPase 1b (PMCA1b), and calbindin-D9k and -D28k [11].
• Estrogen receptor alpha pathway is involved in the regulation of Calbindin-D9k in the uterus of immature rats [12].
• Immunoreactive calbindin-D9K appeared to be extruded from the chondrocytes into the matrix vesicles when the latter were formed during the budding of cell processes [13].
• Immunoreactive calbindin-D9K localization in matrix vesicle-initiated calcification in rat epiphyseal cartilage: an immunoelectron microscope study [13].
• Calbindin-D9k and parvalbumin are exclusively located along basolateral membranes in rat distal nephron [14].

Associations of S100g with chemical compounds

• The 9,000 Mr calcium-binding protein calbindin-D9k (CaBP9k) is markedly induced by 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] in mammalian intestine [15].
• It has been demonstrated in our previous studies that Calbindin-D9k (CaBP-9k) is a potent biomarker for screening estrogen-like chemicals in the rat model [12].
• The mRNA levels of renal 25-hydoxyvitamin D 24-hydroxylase (24OHase) increased, whereas those of renal 25-hydroxyvitamin D 1-alpha hydroxylase (1alpha-hydroxylase), duodenal transient receptor potential cation channel, subfamily V, member 6 (TRPV6), TRPV5, and calbindin-D9k were all decreased [16].
• Effect of 1,25,28-trihydroxyvitamin D2 and 1,24,25-trihydroxyvitamin D3 on intestinal calbindin-D9K mRNA and protein: is there a correlation with intestinal calcium transport [17]?
• Calcitriol increased total cell and brush border calbindin-D9K (P < .0001); this variation paralleled plasma calcitriol levels in both strains [18].

Regulatory relationships of S100g

• Calcium transport by the Ca2(+)-pumping ATPase in rat duodenal basolateral-enriched membrane vesicles was stimulated by synthetic calbindin-D9k in a similar fashion to the purified natural protein [19].

Other interactions of S100g

• Effect of genistein as a selective estrogen receptor beta agonist on the expression of Calbindin-D9k in the uterus of immature rats [20].
• Furthermore, comparison of the transient elevation of calcium absorption by OCT with its more prolonged effects on PTH and calbindin D9k indicates that each action of vitamin D compounds has a distinct biological half-life [21].
• MC903, a low calcemic analog with a relative high affinity for the vitamin D receptor and a short half-life, increased renal calbindin-D28k without increasing ionized calcium or intestinal calbindin-D9k [22].
• In the study presented here, parvalbumin, calbindin-D9k, and calbindin-D28k were localized precisely by immunocytochemistry in rat kidney [14].
• Moreover, in ameloblasts, expression of calbindin-D28K preceded that of calbindin-D9K [23].

Analytical, diagnostic and therapeutic context of S100g

• Calbindin-D9K immunoreactivity was localized by electron microscopy in rat calcifying epiphyseal plate cartilage [13].
• Radioimmunoassays showed that calbindin-D28k accounts for approximately 0.1% of cytosolic proteins in the ectomesenchymal fraction and 1% in the epithelial fraction of the rat incisor and is 100-fold more concentrated than calbindin-D9k in both tissue types [24].
• To investigate the potential role of altered gene expression in these decreases, we measured, by Northern blot analyses, the abundances of alkaline phosphatase and calbindin-D9K mRNAs in the proximal regions of the small intestines of 14-week-old SHR and control Wistar-Kyoto (WKY) rats [25].
• We have used organ cultures of 18-day fetal rat duodena to study the regulation of calbindin-D9K (CaBP9K) gene expression by 1,25-dihydroxycholecalciferol (1,25(OH)2D3) and calcium [26].
• Calbindin-D9K (immunoassay) was decreased in SHR vs WKY rats by 27%, 64%, and 67% in segments A1, B1, and C1, respectively (P < 0.01); its mRNA was decreased to a similar extent (69%, 82%, and 80%, respectively; P < 0.002 by analysis of variance) [25].

References