17-Oxidoreduction of 17β-Estradiol, Estrone and Their 3-Sulfates by Kidney Slices from Guinea Pig and Human

1975 ◽  
Vol 53 (12) ◽  
pp. 1333-1336 ◽  
Author(s):  
R. Hobkirk ◽  
Mona Nilsen ◽  
Barbara Jennings
Keyword(s):  
Guinea Pig ◽  
Marked Reduction ◽  
Human Kidney ◽  
Kidney Cortex ◽  
Limited Extent ◽  
Tissue Slices ◽  
Ample Evidence ◽  
Sulfatase Activity ◽  
17Β Estradiol ◽  
Dehydrogenation Reactions

Slices of whole kidney and kidney cortex from the female guinea pig catalyzed a marked reduction of estrone 3-sulfate (E13S) and estrone (E1) to 17β-estradiol 3-sulfate (E23S) and 17β-estradiol (E2), respectively, as well as the reverse (dehydrogenation) reactions. Slices of medulla did not appear active in E23S–E13S interconversion but did possess the ability to interconvert E2 and E1, besides possessing considerable sulfatase activity. The use of [3H-35S]E13S and [3H-35S]E23S as substrates, together with a demonstrated lack of estrogen sulfate synthesis by the tissue slices, provided ample evidence that the intact sulfates were involved in direct oxidoreduction. Slices of human kidney cortex catalyzed the reduction of E13S to a very limited extent. Slices of whole kidney and of cortex from guinea pig formed small amounts of estrogen glucuronide(s).

Direct Conversion of 17β-Estradiol-3-ghicosiduronate and 17β-Estradiol-3-sulfate to their 17-Keto Forms by Human Kidney Homogenates

1974 ◽  
Vol 52 (1) ◽  
pp. 15-20 ◽  
Author(s):  
R. Hobkirk ◽  
R. N. Green ◽  
M. Nilsen ◽  
B. A. Jennings
Keyword(s):  
Human Kidney ◽  
Direct Conversion ◽  
Reverse Reaction ◽  
Experimental Conditions ◽  
Glucuronidase Activity ◽  
Sulfatase Activity ◽  
17Β Estradiol ◽  
Low Activity

Labelled 17β-estradiol-3-glucosiduronate and 17β-estradiol-3-sulfate were both directly dehydrogenated to their respective 17-keto forms on incubation with human kidney homogenates. NAD increased the conversion to a greater extent than did NADP. The reverse reaction, even in the presence of NADH or NADPH was not found to a measurable extent, presumably because of rapid oxidation of the cofactors. High or low activity towards the conjugates was accompanied by high or low activity, respectively, towards free 17β-estradiol. These dehydrogenase activities were particularly high in the medulla of one kidney so investigated. Considerable sulfatase activity was usually encountered in these homogenates but little β-glucuronidase activity was demonstrated under the experimental conditions.

scholarly journals Analyse der strahleninduzierten Elektrolytveränderungen in Nierenschnitten

1960 ◽  
Vol 15 (10) ◽  
pp. 671-675
Author(s):  
H. Breuer ◽  
H. K. Parchwitz
Keyword(s):  
Oxygen Uptake ◽  
Guinea Pig ◽  
Transport Mechanism ◽  
Kidney Cortex ◽  
Concentration Gradients ◽  
Tissue Slices ◽  
Pig Kidney ◽  
X Irradiation ◽  
Cortex Slices ◽  
Kidney Cortex Slices

The effect of X-irradiation (14 000 r-58 000 r) on the movements of potassium and sodium in guinea pig kidney cortex slices after incubation under various conditions has been investigated. In addition, the oxygen uptake of the tissue slices has been measured.The concentration gradients of potassium and sodium between slices and medium were reduced after X-irradiation. However, this reduction was only found when the slices were incubated at 37°C. At lower temperatures no effect of X-irradiation was observed. The oxygen uptake of the kidney cortex slices remained unaffected by X-irradiation.The experiments described in the present paper suggest that X-irradiation acts on the ion transport mechanism itself rather than on energy supplying processes.

Measurement and Distribution of Zinc, Cadmium, and Mercury in Human Kidney Tissue

1972 ◽  
Vol 18 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Hugh D Livingston
Keyword(s):  
Neutron Activation ◽  
Gamma Spectrometry ◽  
Kidney Tissue ◽  
Germanium Detector ◽  
Human Kidney ◽  
Kidney Cortex ◽  
Outer Cortex ◽  
Tissue Slices ◽  
Outer Medulla ◽  
Zinc Cadmium

Abstract Simultaneous analyses of human kidney cortex tissues for zinc, cadmium, and mercury were made by neutron activation combined with either radiochemical separation prior to counting or direct germanium detector gamma spectrometry. For some samples from adults and infants, analyses were made on successive tissue slices from the outer cortex to the inner medulla. Zinc and cadmium show a concentration gradient, with the highest concentrations at the outer medulla. Mercury was preferentially concentrated deeper in the cortex. All three metals, and especially cadmium, are found in higher concentrations in adult than in infant kidneys. A mechanism for the rapid increase in renal cadmium is proposed. The heterogeneous renal distribution of the elements indicates that careful sampling is necessary in any comparative study of their occurrence in human kidney tissue.

Formation of Estrogen Glucosiduronates by Human Kidney Homogenates

1974 ◽  
Vol 52 (1) ◽  
pp. 9-14 ◽  
Author(s):  
R. Hobkirk ◽  
R. N. Green ◽  
M. Nilsen ◽  
B. A. Jennings
Keyword(s):  
Human Kidney ◽  
Kidney Cortex ◽  
Partition Chromatography ◽  
Experimental Conditions ◽  
17Β Estradiol ◽  
Acid Metabolites ◽  
Steroid Conjugates

17β-Estradiol-6,7-3H (E2), 17β-estradiol-6,7-3H-3-sulfate (E23S), and estriol-6,7-3H (E3) were each incubated with human kidney homogenates in the presence of uridine diphosphoglucuronic acid. Metabolites were purified by DEAE-Sephadex and Celite partition chromatography and were identified by crystallization with carrier steroid conjugates and free steroids. E2 was converted to a small but definite extent (< 0.1–5%) to estrone-3-glucosiduronate, 17β-estradiol-3-glucosiduronate, and 17β-estradiol-17-glucosiduronate, the latter conjugate usually predominating. Under the experimental conditions E2 was a better precursor of all three conjugates than was E23S. In one experiment where kidney cortex and medulla were incubated separately with E2, the former was some 20 times more efficient in glucosiduronate synthesis. E3 was converted to the extent of 52–91% to estriol-16-glucosiduronate by whole kidney homogenates.

Investigation of the Thermal and Injury Behavior During Microwave Thermal Therapy of Porcine Kidney

2002 ◽  
Author(s):  
Xiaoming He ◽  
Shawn Mcgee ◽  
James E. Coad ◽  
Paul A. Iaizzo ◽  
David J. Swanlund ◽  
...  
Keyword(s):  
Thermal Model ◽  
Histological Study ◽  
Kidney Cortex ◽  
Cellular Injury ◽  
Bioheat Equation ◽  
Tissue Slices ◽  
Thermal Histories ◽  
Microwave Probe

In this paper, we report on the characterization of microwave therapy of normal porcine kidneys both in vitro and in vivo. This technology is being developed for eventual use in the treatment of small renal cell carcinoma (RCC) by minimally invasive procedures. During experiments, microwave energy was applied through an interstitial microwave probe (Urologix, Plymouth, MN) to the kidney cortex with occasional involvement of the kidney medulla. The thermal histories at several locations were recorded. After treatment, the kidneys were bisected and small tissue slices were cut out at approximately the same depth as the thermal probes. The tissue slices were further processed for histological study. Both cellular injury and the area of microvascular stasis were quantitatively evaluated by histology. Absolute rate kinetic models of cellular injury and vascular stasis were developed and fit to this data. A 3-D finite element thermal model based on the Pennes Bioheat equation was developed and solved using a commercial software package (ANSYS, V5.7). The Specific Absorption Rate (SAR) of the microwave probe was measured experimentally in tissue equivalent gel-like solution. The thermal model was first validated by the measured in vitro thermal histories. It was then used to determine the blood perfusion term in vivo.

Effects of estrogen on action potential and membrane currents in guinea pig ventricular myocytes

1999 ◽  
Vol 277 (2) ◽  
pp. H826-H833 ◽  
Author(s):  
Seiko Tanabe ◽  
Toshio Hata ◽  
Masayasu Hiraoka
Keyword(s):  
Guinea Pig ◽  
Action Potential ◽  
Action Potentials ◽  
Voltage Dependence ◽  
Ventricular Myocytes ◽  
Membrane Currents ◽  
Patch Clamp Technique ◽  
17Β Estradiol ◽  
Electrophysiological Effects ◽  
Ionic Basis

To explore a possible ionic basis for the prolonged Q-T interval in women compared with that in men, we investigated the electrophysiological effects of estrogen in isolated guinea pig ventricular myocytes. Action potentials and membrane currents were recorded using the whole cell configuration of the patch-clamp technique. Application of 17β-estradiol (10–30 μM) significantly prolonged the action potential duration (APD) at 20% (APD20) and 90% repolarization (APD90) at stimulation rates of 0.1–2.0 Hz. In the presence of 30 μM 17β-estradiol, APD20 and APD90 at 0.1 Hz were prolonged by 46.2 ± 17.1 and 63.4 ± 11.7% of the control ( n = 5), respectively. In the presence of 30 μM 17β-estradiol the peak inward Ca2+ current ( I CaL) was decreased to 80.1 ± 2.5% of the control ( n = 4) without a shift in its voltage dependence. Application of 30 μM 17β-estradiol decreased the rapidly activating component of the delayed outward K+ current ( I Kr) to 63.4 ± 8% and the slowly activating component ( I Ks) to 65.8 ± 8.7% with respect to the control; the inward rectifier K+ current was barely affected. The results suggest that 17β-estradiol prolonged APD mainly by inhibiting the I Kcomponents I Krand I Ks.

scholarly journals Fate of glutamate carbon and nitrogen in isolated guinea-pig kidney-cortex tubules. Evidence for involvement of glutamate dehydrogenase in glutamine sythesis from glutamate

1980 ◽  
Vol 188 (3) ◽  
pp. 873-880 ◽  
Author(s):  
G Baverel ◽  
C Genoux ◽  
M Forissier ◽  
M Pellet
Keyword(s):  
Guinea Pig ◽  
Glutamate Dehydrogenase ◽  
Carbon Skeleton ◽  
Kidney Cortex ◽  
Glutamate Metabolism ◽  
Carbon And Nitrogen ◽  
Pig Kidney ◽  
Glutamate Concentration ◽  
Rate Limiting Step

1. The pathways and the fate of glutamate carbon and nitrogen were investigated in isolated guinea-pig kidney-cortex tubules. 2. At low glutamate concentration (1 mM), the glutamate carbon skeleton was either completely oxidized or converted into glutamine. At high glutamate concentration (5 mM), glucose, lactate and alanine were additional products of glutamate metabolism. 3. At neither concentration of glutamate was there accumulation of ammonia. 4. Nitrogen-balance calculations and the release of 14CO2 from L-[1-14C]glutamate (which gives an estimation of the flux of glutamate carbon skeleton through alpha-oxoglutarate dehydrogenase) clearly indicated that, despite the absence of ammonia accumulation, glutamate metabolism was initiated by the action of glutamate dehydrogenase and not by transamination reactions as suggested by Klahr, Schoolwerth & Bourgoignie [(1972) Am. J. Physiol. 222, 813-820] and Preuss [(1972) Am. J. Physiol. 222, 1395-1397]. Additional evidence for this was obtained by the use of (i) amino-oxyacetate, an inhibitor of transaminases, which did not decrease glutamate removal, or (ii) L-methionine DL-sulphoximine, an inhibitor of glutamine synthetase, which caused an accumulation of ammonia from glutamate. 5. Addition of NH4Cl plus glutamate caused an increase in both glutamate removal and glutamine synthesis, demonstrating that the supply of ammonia via glutamate dehydrogenase is the rate-limiting step in glutamine formation from glutamate. NH4Cl also inhibited the flux of glutamate through glutamate dehydrogenase and the formation of glucose, alanine and lactate. 6. The activities of enzymes possibly involved in the glutamate conversion into pyruvate were measured in guinea-pig renal cortex. 7. Renal arteriovenous-difference measurements revealed that in vivo the guinea-pig kidney adds glutamine and alanine to the circulating blood.

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