Tubular GFP uptake pattern in the rat and frog kidneys

Protein Reabsorption in the Amphibian Kidney: Comparative and Evolutionary Aspects

“…The specific fluorescence intensity, maximum fluorescence, and fluorescence density increased in response to increasing doses of GFP and a high positive correlation was revealed. Reabsorption of fluorescent proteins was also time dependent [15,18]. With increasing time after injection, there was an accumulation of vesicles with GFP or YFP and a movement of some fluorescent endocytic vesicles from the apical cytoplasm to perinuclear and basal areas.…”

“…In 30 min, the number of vesicles with internalized protein significantly increased and fluorescent vesicles scattered over the epithelial cell cytoplasm ( Figure 2F). However, in the subsequent period, the number of GFPcontaining vesicles in PT cells and the means of maximum fluorescence have dramatically decreased [15,20]. In 1-2 h, green fluorescent vesicles were absent in the vast majority of PTs.…”

“…Experiments were performed on common frogs (Rana temporaria), newts (Triturus vulgaris), and also Wistar rats (Rattus norvegicus) for some comparisons. We used recombinant fluorescent proteins, green fluorescent protein (GFP), and yellow fluorescent protein (YFP), which turned out to be freely filtered in glomeruli and reabsorbed in epithelial cells of PTs after intravenous injections in frogs, as in rats [15]. Earlier, intestinal absorption and the resulting accumulation of these fluorescent proteins in renal PTs after their intragastric administration were established [16].…”

“…Intracellular distribution of labeled lysozyme in a vesicular compartment of PT cells does not differ fundamentally from the uptake pattern of GFP and YFP ( Figure 2G and H). To discover regularities in protein reabsorption we used a variety of approaches for quantification of protein uptake [15]. After GFP introduction at the doses 0.034-34 μg/100 g body weight, reabsorption of this protein in the kidney was dose-dependent in both frogs and rats [15].…”

“…To discover regularities in protein reabsorption we used a variety of approaches for quantification of protein uptake [15]. After GFP introduction at the doses 0.034-34 μg/100 g body weight, reabsorption of this protein in the kidney was dose-dependent in both frogs and rats [15]. The specific fluorescence intensity, maximum fluorescence, and fluorescence density increased in response to increasing doses of GFP and a high positive correlation was revealed.…”