Immunolocalisation of bilitranslocase in mucosecretory and parietal cells of the rat gastric mucosa

Abstract

Bilitranslocase is a plasma membrane carrier localised at the vascular pole of the rat liver cell, where it mediates uptake of organic anions from the blood into the liver. This carrier is also present in the epithelium of the rat gastric mucosa, with similar molecular mass and functional properties. An immunohistochemical study reveals that both the mucus-secreting cells of the gastric pit and the H+-secreting parietal cells express bilitranslocase. These data point to a possible role of bilitranslocase and of its food-borne substrates (anthocyanins and nicotinic acid) in regulating the function and the permeability of the gastric mucosa.

Hepatic uptake of grape anthocyanins and the role of bilitranslocase

“…These are the mucosecretory cells that pack the most superWcial layer of the gastric glands and the parietal cells that are responsible of acid secretion. This particular cellular localisation of bilitranslocase is compatible with its possible role in the permeation of the gastric mucosa by hydrophilic, aromatic compounds introduced into the stomach (Nicolin et al, 2005).…”

“…The organic anion carrier bilitranslocase (Passamonti & Sottocasa, 2002a;Sottocasa, Passamonti, Battiston, Pascolo, & Tiribelli, 1996) is expressed at the vascular domain of the hepatocyte plasma membrane (Baldini, Passamonti, Lunazzi, Tiribelli, & Sottocasa, 1986) and in the stomach (Battiston, Macagno, Passamonti, Micali, & Sottocasa, 1999;Nicolin, Grill, Micali, Narducci, & Passamonti, 2005). In vitro, its transport activity is competitively inhibited by dietary anthocyanins (Passamonti et al, 2002b).…”

Plant Flavonoids—Biosynthesis, Transport and Involvement in Stress Responses

“…This protein is similar to mammalian bilitranslocase (BTL), a plasma membrane carrier localized in liver and gastric mucosa, where it mediates the uptake of the tetrapyrrolic pigment bilirubin and other organic ions, such as dietary anthocyanins and nicotinic acid [55,56]. The BTL-homologue in carnation possesses, similarly to the mammalian carrier, an apparent molecular mass of 38 kDa and is localized in both purified tonoplast and plasma membrane vesicles.…”

Evidence for a putative flavonoid translocator similar to mammalian bilitranslocase in grape berries (Vitis vinifera L.) during ripening

“…Liver BTL has a high-aYnity for dietary Xavonoids (Karawajczyk et al 2007), in particular for anthocyanins (Passamonti et al 2002). The inXux of malvidin 3-glucoside into liver cells has been shown to be strongly inhibited by BTL antibodies (Passamonti et al 2005b), not only showing the functional role of this carrier in the cellular uptake of these plant pigments, but also providing evidence that BTL antibodies can be used as molecular probes of BTL expression (Nicolin et al 2005) and function (Passamonti et al 2000) in other mammalian tissues.…”