scholarly journals NEW OBSERVATIONS ON DISCREPANCIES IN THE HISTOCHEMICAL LOCALIZATION OF LEUCINE AMINOPEPTIDASE

1962 ◽  
Vol 10 (3) ◽  
pp. 315-323 ◽  
Author(s):  
MARVIN M. NACHLAS ◽  
MELVIN M. FRIEDMAN ◽  
ARNOLD M. SELIGMAN
Keyword(s):  
Leucine Aminopeptidase ◽  
Rat Kidney ◽  
Histochemical Demonstration ◽  
Test Tube ◽  
Aminopeptidase Activity ◽  
Diazonium Salts ◽  
Outer Cortex ◽  
Fast Blue ◽  
Ph Buffer ◽  
Inner Cortex

Differences in the localization of leucine aminopeptidase in the cortex of the rat kidney have been reported with two methods employing the same substrate. Test tube and tissue experiments were carried out in an effort to explain the disparity. Substrate concentration, pH, buffer, the use of an activator, duration of incubation and temperature of incubation were found to have insignificant effects. Four important findings were (1) leucine aminopeptidase activity of the inner cortex of the rat kidney assayed two to three times greater than that of the outer cortex, (2) this difference was confirmed by histochemical demonstration with both methods, (3) fast blue B inhibited the enzyme more than fast garnet GBC and fast Corinth V, and (4) fast blue B coupled faster than the other diazonium salts.

INACTIVATION OF ARGININE- AND LYSINE-VASOPRESSIN BY SLICES FROM DIFFERENT ZONES OF THE RAT KIDNEY AND BY RAT LIVER SLICES

1963 ◽  
Vol 44 (4) ◽  
pp. 545-562 ◽  
Author(s):  
N. A. Thorn ◽  
N. B. S. Willumsen
Keyword(s):  
Antidiuretic Hormone ◽  
Rat Kidney ◽  
Extracellular Fluid ◽  
Outer Cortex ◽  
Liver Slices ◽  
Lysine Vasopressin ◽  
Site Of Action ◽  
The Difference ◽  
High Concentrations ◽  
Inner Cortex

ABSTRACT A method was developed for studying the inactivation of antidiuretic hormone in slices from different zones of the rat kidney. The essential features of the method are: The use of thin slices from 4 zones: outer cortex, inner cortex, outer medulla and papilla which are incubated aerobically with the hormone in a medium that has a composition essentially the same as rat extracellular fluid, including a calcium concentration of 2.5 mmol. The inactivation of arginine- and lysine-vasopressin by these slices at 25° C and 37° C for 2 hours was studied. All zones inactivated both vasopressins, but the most marked inactivation activity per mg dry tissue was found in the papillary zone. High concentrations of sodium chloride in the incubation medium did not affect the inactivation of vasopressin by papillary slices. The amounts of arginine- and lysine-vasopressin (expressed in rat pressor units) which were inactivated per mg dry tissue in the different zones during the incubation period were equivalent. Similar results were found in experiments on the inactivation of the two hormones by liver slices. These findings are discussed in relation to the problems of the site of action of antidiuretic hormone and the difference in the antidiuretic response to arginine- and lysine-vasopressin which is found after i. v. injection in the rat.

Quantification of small-scale heterogeneity in aquatic aminopeptidase activity

2020 ◽  
Vol 84 ◽  
pp. 127-140
Author(s):  
BM Gaas ◽  
JW Ammerman
Keyword(s):  
Chlorophyll Fluorescence ◽  
Leucine Aminopeptidase ◽  
Hudson River ◽  
Aminopeptidase Activity ◽  
Small Scale ◽  
Analysis Instrument ◽  
Sequential Samples ◽  
Degree Of Confidence ◽  
The Mean ◽  
Hydrolysis Of

Leucine aminopeptidase (LAP) is one of the enzymes involved in the hydrolysis of peptides, and is sometimes used to indicate potential nitrogen limitation in microbes. Small-scale variability has the potential to confound interpretation of underlying patterns in LAP activity in time or space. An automated flow-injection analysis instrument was used to address the small-scale variability of LAP activity within contiguous regions of the Hudson River plume (New Jersey, USA). LAP activity had a coefficient of variation (CV) of ca. 0.5 with occasional values above 1.0. The mean CVs for other biological parameters—chlorophyll fluorescence and nitrate concentration—were similar, and were much lower for salinity. LAP activity changed by an average of 35 nmol l-1 h-1 at different salinities, and variations in LAP activity were higher crossing region boundaries than within a region. Differences in LAP activity were ±100 nmol l-1 h-1 between sequential samples spaced <10 m apart. Variogram analysis indicated an inherent spatial variability of 52 nmol l-1 h-1 throughout the study area. Large changes in LAP activity were often associated with small changes in salinity and chlorophyll fluorescence, and were sensitive to the sampling frequency. This study concludes that LAP measurements in a sample could realistically be expected to range from zero to twice the average, and changes between areas or times should be at least 2-fold to have some degree of confidence that apparent patterns (or lack thereof) in activity are real.

Leucine Aminopeptidase Activity in Mast Cells

Nature ◽  
1959 ◽  
Vol 183 (4653) ◽  
pp. 51-52 ◽  
Author(s):  
O. BRAUN-FALCO ◽  
K. SALFELD
Keyword(s):  
Mast Cells ◽  
Leucine Aminopeptidase ◽  
Aminopeptidase Activity

scholarly journals Effect of lead on leucine aminopeptidase activity in human blood.

1980 ◽  
Vol 18 (1) ◽  
pp. 55-57
Author(s):  
Momoko CHIBA ◽  
Kazuko OGIHARA ◽  
Masakazu KIKUCHI
Keyword(s):  
Human Blood ◽  
Leucine Aminopeptidase ◽  
Aminopeptidase Activity

scholarly journals THE STAGES IN CALCIFICATION OF THE RAT KIDNEY AFTER THE ADMINISTRATION OF URANIUM NITRATE

1953 ◽  
Vol 97 (5) ◽  
pp. 681-694 ◽  
Author(s):  
Lewis K. Dahl
Keyword(s):  
Ferrous Iron ◽  
Rat Kidney ◽  
Cellular Damage ◽  
Appreciable Amount ◽  
Wide Range ◽  
Uranium Nitrate ◽  
Speed Of Evolution ◽  
Dose Levels ◽  
Convoluted Tubules ◽  
Inner Cortex

The anatomical and histochemical alterations in rat kidneys after the parenteral administration of uranium nitrate [UO2(NO3)2·6H2O] have been studied. The histological effects produced by this agent over a wide range of dose levels were nearly identical in character and differed principally in their speed of evolution. The deposition of calcium always began at foci in the cytoplasm of the cells of the proximal convoluted tubules of the inner cortex. It remained intracellular until the cell boundaries were destroyed. Deposits of calcium could be found before any other cellular damage could be demonstrated by histological examination. Later, when degeneration and necrosis were present, the foci of calcification were imperfectly related to them in location or degree. In contrast, the amount of calcification was correlated with the dose of uranium nitrate, being greatest in the kidneys of rats that received 20 mg./kg., next greatest in the 30 mg./kg. rats, less in the 10 mg./kg. rats, and slight in those that received 2 mg./kg. Histochemical stains for ferric and ferrous iron, chondroitinsulfate, and polysaccharides gave results that were negative or unrelated to the deposits of calcium, thus making it unlikely that these substances held any appreciable amount of calcium in the tissue. Yet it is clear that some anion other than phosphate must be combined with part of the calcium; the results with the alizarin and von Kóssa stains confirmed an earlier result (1) in showing that the first deposits of calcium are formed without comparable accumulations of phosphate.

Continuous measurement of tissue blood flow by laser-Doppler spectroscopy

1977 ◽  
Vol 232 (4) ◽  
pp. H441-H448 ◽  
Author(s):  
M. D. Stern ◽  
D. L. Lappe ◽  
P. D. Bowen ◽  
J. E. Chimosky ◽  
G. A. Holloway ◽  
...  
Keyword(s):  
Blood Flow ◽  
Line Width ◽  
Rat Kidney ◽  
Tissue Perfusion ◽  
Laser Doppler ◽  
Renal Physiology ◽  
Tissue Blood Flow ◽  
Outer Cortex ◽  
Promising Tool

Laser light scattered from tissue in vivo is broadened in line width as a result of the Doppler shift produced by moving red cells in the microcirculation. A feasibility study was carried out to demonstrate use of this effect to measure and monitor tissue blood flow. Light from a helium-neon laser illuminated a 1-mm area of tissue (human skin or rat renal cortex), and the backscattered light was detected with a photomultiplier. The spectrum of the Doppler beat notes was analyzed directly with a digital spectrum analyzer, or processed by analog circuitry to yield a flow parameter based on the root-mean-square Doppler line width. This parameter was compared with 133Xe washout in the skin of volunteers subjected to UV-induced erythema and the skin of volunteers subjected to UV-induced erythema and was found to vary in an approximately linear manner with skin blood flow. The laser instrument provided continuous monitoring of blood flow fluctuations, including the pulsatile component. The instrument was used to monitor flow in the outer cortex of the rat kidney during administration of norepinephrine, angiotensin, hydralazine, dextran, dopamine, nitroprusside, and angiotensin blocked by saralasin. Dynamic and steady-state responses were consistent with known pharmacology and renal physiology, and with the assumption that vasoconstrictor angiotensin II receptors in the kidney are accessible to blood-borne inhibitors. The laser-Doppler method is a promising tool for rapid monitoring of dynamic changes in tissue perfusion.

Effects of angiotensin II on regional afferent and efferent arteriole dimensions and the glomerular pole

2000 ◽  
Vol 279 (2) ◽  
pp. R629-R638 ◽  
Author(s):  
Kate M. Denton ◽  
Warwick P. Anderson ◽  
Raja Sinniah
Keyword(s):  
Angiotensin Ii ◽  
Arterial Pressure ◽  
Capillary Pressure ◽  
Ang Ii ◽  
Similar Extent ◽  
Outer Cortex ◽  
Efferent Arteriole ◽  
Vascular Casting ◽  
Cortical Regions ◽  
Inner Cortex

The diversity of renal arteriole diameters in different cortical regions has important consequences for control of glomerular capillary pressure. We examined whether intrarenal angiotensin II (ANG II; 0.1, 1, or 5 ng · kg−1 · min−1) in anesthetized rabbits acts preferentially on pre- or postglomerular vessels using vascular casting. ANG II produced dose-related reductions in afferent and efferent diameters in the outer, mid, and inner cortex, without effecting arterial pressure. Afferent diameter decreased more than efferent in the outer and mid cortex ( P < 0.05) but by a similar extent in juxtamedullary nephrons ( P = 0.58). Calculated efferent resistance increased more than afferent, especially in the outer cortex (127 vs. 24 units; 5 ng · kg−1 · min−1 ANG II). ANG II produced significant dose-related increases in the distance between the arterioles at the entrance to the glomerular pole in all regions. Thus afferent diameter decreased more in response to ANG II, but efferent resistance rose more due to smaller resting luminal dimensions. The results also indicate that glomerular pole dimensions change in response to ANG II.

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