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Analysis of the protein related receptor GPR92 in G-cells.

Rettenberger AT, Schulze W, Breer H, Haid D - Front Physiol (2015)

Bottom Line: Our previous studies have shown that G-cells express suitable receptor types, most notably the peptone-receptor GPR92 and the amino acid receptors GPRC6A and CaSR; however, their relative importance remained unclear.The results indicate that the relative amount of receptor protein for GPR92 was much higher than for the receptor types GPRC6A and CaSR.These findings support the notion that the peptone-receptor GPR92 may be particularly relevant for sensing partially digested protein products.

View Article: PubMed Central - PubMed

Affiliation: Institute of Physiology, University of Hohenheim Stuttgart, Germany.

ABSTRACT
A continuous assessment of ingested food in the gastric lumen is essential for fine-tuning the digestive activities, including the secretion of the regulatory hormones such as gastrin. It has been proposed that G-cells may be able to sense the amount of ingested proteins and adjust the secretion of gastrin accordingly. Our previous studies have shown that G-cells express suitable receptor types, most notably the peptone-receptor GPR92 and the amino acid receptors GPRC6A and CaSR; however, their relative importance remained unclear. To determine the relative quantity of each receptor type, individual G-cells isolated from the transgenic mouse line mGas-EGFP were analyzed by means of a Liquid Chromatography Tandem-Mass Spectrometry (LC-MS/MS) procedure. The results indicate that the relative amount of receptor protein for GPR92 was much higher than for the receptor types GPRC6A and CaSR. These findings support the notion that the peptone-receptor GPR92 may be particularly relevant for sensing partially digested protein products. This view was supported by the finding that a high-protein diet affected the expression level of the peptone-receptor GPR92 in the gastric antrum as well as in the circumvallate papillae.

No MeSH data available.


Related in: MedlinePlus

Quantitative PCR (qPCR) analysis of mRNA for the receptor types GPR92, GPRC6A, and CaSR in the murine gastric antrum from normal fed mice. (A) The relative expression levels of the three receptor types in the antral mucosa from five different mice. In all cases the results indicate the highest expression rates for the peptone-receptor GPR92.(B) Mean transcript levels of GPR92, GPRC6A and CaSR from A1-A5 shown in (A). The values for GPR92 are 4.6-fold higher than those for GPRC6A (P = 0.004) and 8.1-fold higher than for CaSR (P = 0.0003). Ribosomal protein L8 (RpL8) was used as an internal control. Relative expression was calculated using the formula: ΔCt = ECt(target)−Ct(reference) with corresponding efficiencies (EGPR92: 1.988, EGPRC6A: 1.967 and ECaSR: 1.965). Data are generated in triplicate are expressed as mean ± SD with n = 5 mice. Statistically significant results determined by the unpaired t-test (***P = 0.001).
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Figure 1: Quantitative PCR (qPCR) analysis of mRNA for the receptor types GPR92, GPRC6A, and CaSR in the murine gastric antrum from normal fed mice. (A) The relative expression levels of the three receptor types in the antral mucosa from five different mice. In all cases the results indicate the highest expression rates for the peptone-receptor GPR92.(B) Mean transcript levels of GPR92, GPRC6A and CaSR from A1-A5 shown in (A). The values for GPR92 are 4.6-fold higher than those for GPRC6A (P = 0.004) and 8.1-fold higher than for CaSR (P = 0.0003). Ribosomal protein L8 (RpL8) was used as an internal control. Relative expression was calculated using the formula: ΔCt = ECt(target)−Ct(reference) with corresponding efficiencies (EGPR92: 1.988, EGPRC6A: 1.967 and ECaSR: 1.965). Data are generated in triplicate are expressed as mean ± SD with n = 5 mice. Statistically significant results determined by the unpaired t-test (***P = 0.001).

Mentions: In order to get some first insight, we set out to determine the relative expression levels of the three receptor types in tissue samples from the gastric antrum region where G-cells account for 60% of the enteroendocrine cell types (Sachs et al., 1997). The results of quantitative real-time polymerase chain reaction (qPCR) of antral tissues are depicted in Figure 1. The data shown in Figure 1A represent the relative amounts of receptor transcripts in the antrum mucosa determined for five mice. In all cases the highest levels of mRNA were found for the peptone-receptor GPR92; the transcript levels for GPRC6A and CaSR were much lower. This general trend was reflected in the mean transcript levels of the five mice (Figure 1B) showing that mRNA amounts for GPR92 were 4.6-fold higher than for GPRC6A (P = 0.0004, Figure 1B) and 8.1-fold higher than for CaSR (P = 0.0003; Figure 1B).


Analysis of the protein related receptor GPR92 in G-cells.

Rettenberger AT, Schulze W, Breer H, Haid D - Front Physiol (2015)

Quantitative PCR (qPCR) analysis of mRNA for the receptor types GPR92, GPRC6A, and CaSR in the murine gastric antrum from normal fed mice. (A) The relative expression levels of the three receptor types in the antral mucosa from five different mice. In all cases the results indicate the highest expression rates for the peptone-receptor GPR92.(B) Mean transcript levels of GPR92, GPRC6A and CaSR from A1-A5 shown in (A). The values for GPR92 are 4.6-fold higher than those for GPRC6A (P = 0.004) and 8.1-fold higher than for CaSR (P = 0.0003). Ribosomal protein L8 (RpL8) was used as an internal control. Relative expression was calculated using the formula: ΔCt = ECt(target)−Ct(reference) with corresponding efficiencies (EGPR92: 1.988, EGPRC6A: 1.967 and ECaSR: 1.965). Data are generated in triplicate are expressed as mean ± SD with n = 5 mice. Statistically significant results determined by the unpaired t-test (***P = 0.001).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4585063&req=5

Figure 1: Quantitative PCR (qPCR) analysis of mRNA for the receptor types GPR92, GPRC6A, and CaSR in the murine gastric antrum from normal fed mice. (A) The relative expression levels of the three receptor types in the antral mucosa from five different mice. In all cases the results indicate the highest expression rates for the peptone-receptor GPR92.(B) Mean transcript levels of GPR92, GPRC6A and CaSR from A1-A5 shown in (A). The values for GPR92 are 4.6-fold higher than those for GPRC6A (P = 0.004) and 8.1-fold higher than for CaSR (P = 0.0003). Ribosomal protein L8 (RpL8) was used as an internal control. Relative expression was calculated using the formula: ΔCt = ECt(target)−Ct(reference) with corresponding efficiencies (EGPR92: 1.988, EGPRC6A: 1.967 and ECaSR: 1.965). Data are generated in triplicate are expressed as mean ± SD with n = 5 mice. Statistically significant results determined by the unpaired t-test (***P = 0.001).
Mentions: In order to get some first insight, we set out to determine the relative expression levels of the three receptor types in tissue samples from the gastric antrum region where G-cells account for 60% of the enteroendocrine cell types (Sachs et al., 1997). The results of quantitative real-time polymerase chain reaction (qPCR) of antral tissues are depicted in Figure 1. The data shown in Figure 1A represent the relative amounts of receptor transcripts in the antrum mucosa determined for five mice. In all cases the highest levels of mRNA were found for the peptone-receptor GPR92; the transcript levels for GPRC6A and CaSR were much lower. This general trend was reflected in the mean transcript levels of the five mice (Figure 1B) showing that mRNA amounts for GPR92 were 4.6-fold higher than for GPRC6A (P = 0.0004, Figure 1B) and 8.1-fold higher than for CaSR (P = 0.0003; Figure 1B).

Bottom Line: Our previous studies have shown that G-cells express suitable receptor types, most notably the peptone-receptor GPR92 and the amino acid receptors GPRC6A and CaSR; however, their relative importance remained unclear.The results indicate that the relative amount of receptor protein for GPR92 was much higher than for the receptor types GPRC6A and CaSR.These findings support the notion that the peptone-receptor GPR92 may be particularly relevant for sensing partially digested protein products.

View Article: PubMed Central - PubMed

Affiliation: Institute of Physiology, University of Hohenheim Stuttgart, Germany.

ABSTRACT
A continuous assessment of ingested food in the gastric lumen is essential for fine-tuning the digestive activities, including the secretion of the regulatory hormones such as gastrin. It has been proposed that G-cells may be able to sense the amount of ingested proteins and adjust the secretion of gastrin accordingly. Our previous studies have shown that G-cells express suitable receptor types, most notably the peptone-receptor GPR92 and the amino acid receptors GPRC6A and CaSR; however, their relative importance remained unclear. To determine the relative quantity of each receptor type, individual G-cells isolated from the transgenic mouse line mGas-EGFP were analyzed by means of a Liquid Chromatography Tandem-Mass Spectrometry (LC-MS/MS) procedure. The results indicate that the relative amount of receptor protein for GPR92 was much higher than for the receptor types GPRC6A and CaSR. These findings support the notion that the peptone-receptor GPR92 may be particularly relevant for sensing partially digested protein products. This view was supported by the finding that a high-protein diet affected the expression level of the peptone-receptor GPR92 in the gastric antrum as well as in the circumvallate papillae.

No MeSH data available.


Related in: MedlinePlus