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F BERGLUND

Publications and source records attributed to F BERGLUND.

At least 19 recordsLinked to original sources
PubMed1958

Tubular secretion of creatine, trimethylamine oxide, and other organic bases by the aglomerular kidney of Lophius americanus.

Creatine and trimethylamine oxide (TMAO) are the chief nitrogenous constituents of normal Lophius urine, and both of these organic bases characteristically have high urine/plasma concentration ratios. Competition studies involving various organic bases indicate that creatine and TMAO are excreted independently by separate transport mechanisms. TMAO excretion is inhibited competitively by tetraethylammonium ion (TEA) and by cyanine dye No. 863-compounds previously shown to be transferred actively by an organic base-secreting mechanism of general occurrence among vertebrates. TEA does not inhibit competitively the active tubular reabsorption of TMAO in Squalus with doses which markedly depress its tubular excretion in Lophius. Glycine, which inhibits creatine reabsorption in the dog, does not interfere competitively with its secretion in Lophius.

Amines↗
PubMed1958

Renal tubular transport of inorganic divalent ions by the aglomerular marine teleost, Lophius americanus.

A characterization was attempted of the mechanisms involved in the tubular transport of inorganic divalent ions by the aglomerular kidney of Lophius, attention being paid particularly to the possible existence of transport maxima (Tm) and to competition for transport among related substances undergoing tubular excretion. Excretory rates of divalent ions in non-treated fish during standard laboratory conditions paralleled spontaneous changes in urine flow. Tm rates of excretion were reached for magnesium, sulfate, and thiosulfate with corresponding plasma levels of 2 to 5, 5 to 17, and 4 to 12 microM/ml. respectively. Elevation of magnesium chloride levels in plasma markedly depressed calcium excretion; sodium thiosulfate similarly depressed sulfate excretion. Experimental observations suggest the existence of a transport system for divalent cations separate from another for divalent anions. Within each transport system the ion with the higher excretion rate depressed competitively transfer of the other ion. Neither system was influenced by probenecid (benemid) in doses which markedly depressed the simultaneous excretion rate of p-aminohippuric acid.

Animals↗
PubMed1956

Osmotic diuresis and its effect on total electrolyte distribution in plasma and urine of the aglomerular teleost, Lophius americanus.

Quantitative evaluations have been made of the chief anions and cations in plasma, urine, and pericardial fluid taken both from freshly captured goosefish and from those undergoing "laboratory diuresis." Measurements included: Na, K, Ca, Mg, Cl, SO(4), PO(4), protein, HCO(3), NH(3), pH, titratable acidity, freezing point depression, creatine, trimethylamine oxide, and plasma volume. The total patterns of electrolyte distribution in these body fluids are presented. The morphologically undifferentiated aglomerular tubule acts as a barrier to the free diffusion of monovalent electrolytes, while transporting actively the divalent ions, especially Mg. Urine taken from freshly captured fish is hypotonic to plasma, low in electrolyte, and as much as 50 per cent of its total osmolarity is accounted for by nitrogenous components. Of these creatine is transported most actively by the renal tubule cells. With the onset of diuresis immediately after capture, plasma osmolarity slowly rises and urine suddenly becomes isotonic with plasma as chloride floods into the urine. The active movement of Mg continues during diuresis and urine/plasma concentration ratios of 100 or more are sustained for days while the animals are kept in the laboratory. Na follows chloride and never reaches 50 per cent of plasma values, and K never appears in urine in more than mere traces. Electrolytes in this system are viewed as not being in true equilibrium but rather as constituting a biological steady state with the distribution across renal cells being maintained against passive diffusion by the expenditure of cellular energy.

Animals↗