Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-1424
    Keywords: Bufo marinus ; triiodothyronine ; hormonal domain ; aldosterone ; sodium butyrate ; transepithelial sodium transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary In the urinary bladder of the toadBufo marinus, the basal rate of synthesis of a number of proteins was modulated in a bidirectional way (i.e., induced or repressed) by aldosterone and by triiodothyronine (T3). Each hormone was therefore characterized by a distinct domain of response. When both hormones were added simultaneously, the two domains consistently overlapped at least for one protein, termed AIP-1, or aldosterone-induced protein 1 (M r≈65 kilodaltons,p i=6.7, as analyzed by two-dimension gel electrophoresis). The physiological role of AIP-1 is unknown, but could be related to the late mineralocorticoid response. In five experiments, T3 (60nm, 18-hr incubation) consistently repressed AIP-1, while aldosterone-dependent sodium transport (late response) was significantly inhibited, as previously described. The repression of AIP-1 was also observed as early as 6 hr after aldosterone addition. In addition, sodium butyrate (3mm), which was previously shown to also selectively inhibit the late mineralocorticoid response, was also able to repress AIP-1. Our results suggest that AIP-1, is one of the proteins involved in the mediation of the late mineralocorticoid response.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 77 (1984), S. 15-23 
    ISSN: 1432-1424
    Keywords: aldosterone ; triidothyronine ; thyromimetic drugs ; sodium transport ; toad bladder ; Bufo marinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Aldosterone increases transepithelial Na+ transport in the urinary bladder ofBufo marinus. The response is characterized by 3 distinct phases: 1) a lag period of about 60 min, ii) an initial phase (early response) of about 2 hr during which Na+ transport increases rapidly and transepithelial electrical resistance falls, and iii) a late phase (late response) of about 4 to 6 hr during which Na+ transport still increases significantly but with very little change in resistance. Triiodothyronine (T3, 6nm) added either 2 or 18 hr before aldosterone selectively antagonizes the late response. T3 per se (up to 6nm) has no effect on base-line Na+ transport. The antagonist activity of T3 is only apparent after a latent period of about 6 to 8 hr. It is not rapidly reversible after a 4-hr washout of the hormone. The effects appear to be selective for thyromimetic drugs since reverse T3 (rT3) is inactive and isopropyldiiodothyronine (isoT2) is more active than T3. The relative activity of these analogs corresponds to their relative affinity for T3 nuclear binding sites which we have previously described. Our data suggest that T3 might control the expression of aldosterone by regulating gene expression, e.g. by the induction of specific proteins, which in turn will inhibit the late mineralocorticoid response, without interaction with the early response.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-1424
    Keywords: aldosterone ; triiodothyronine ; sodium transport ; mineralocorticoid receptors ; bufo marinus ; down regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary In the urinary bladder of the toadBufo marinus triiodothyronine selectively inhibits the late effect of aldosterone on Na+ transport. We have investigated whether T3 might mediate its antimineralocorticoid action by controlling: i) the level of aldosterone binding sites in the soluble (cytosolic) pool isolated from tissues treated with T3 (60nm) for up to 20 hr of incubation; ii) the kinetics of uptake of3H-aldosterone into cytoplasmic and nuclear fractions after 2 or 20 hr of exposure to T3. The number and the affinity of Type I (high affinity, low capacity) and Type II (low affinity, high capacity) cytosolic binding sites (measured at 0°C) did not vary significantly after 18 hr of exposure to T3, while aldosterone-dependent Na+ transport was significantly inhibited. In addition, T3 did not modify the kinetics of uptake (90 min) of3H-aldosterone into cytoplasmic and nuclear fractions of toad bladder incubatedin vitro at 25°C. By contrast, aldosterone itself was able to down-regulate its cytosolic and nuclear binding sites after an 18-hr exposure to the steroid hormone (10 or 80nm). T3 slightly (20%) but significantly potentiated the down regulation of nuclear binding sites. In conclusion, T3 does not appear to have major effects on the regulation of the aldosterone receptor, which could explain in a simple manner its antimineralocorticoid action.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 41 (1978), S. 149-166 
    ISSN: 1432-1424
    Keywords: poly(A)(+)mRNA ; poly(A)(-)mRNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Previous studies have shown that aldosterone increases transepithelial active Na+ transport after a latent period of about 60 min and incorporation of3H-uridine into polyadenylated RNA (poly(A)(+)RNA) (putatively poly(A)(+)mRNA) as early as 30 min after aldosterone addition. To assess the physiological importance of this pathway, the effects of 3′deoxyadenosine and actinomycin D were compared in studies on the urinary bladder of the toadBufo marinus. 3′deoxyadenosine (30 μg/ml) only partially, though significantly, inhibited the aldosterone-dependent increase in Na+ transport measured as short-circuit current (scc). The incorporation of3H-uridine into poly(A) (+)RNA was inhibited by 70 to 80%. In contrast, Actinomycin D (2 μg/ml) totally inhibited the aldosterone-dependent increase in scc, and the incorporation of3H-uridine into poly(A)(+)RNA by 68 to 75%. 3′deoxyadenosine or actinomycin D alone had no significant effects on baseline scc, while inhibiting poly(A)(+)RNA to the same extent. The differential effects of deoxyadenosine and actinomycin on aldosterone-dependent Na+ transport may be related to their different sites of action on RNA synthesis: both drugs inhibited, to a similar extent, cytoplasmic poly(A)(+)mRNA; however, 3′deoxyadenosine, in contrast to Actinomycin D, failed to inhibit poly(A)(-)RNA, sedimenting between 4S and 18S (putatively poly(A)(-)mRNA). We conclude that the mineralocorticoid action of aldosterone during the first three hours depends on the synthesis of both poly(A)(+)mRNA and poly(A)(-)mRNA.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' journal of analytical chemistry 359 (1997), S. 382-384 
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A double focusing ICP-MS, equipped with a Micro Concentric Nebulizer, has been used to determine concentrations and isotopic ratios of lead in recent snow samples (1993–1996) from high alpine sites in Switzerland. Concentrations varied between 0.02 ± 0.002 and 5.5 ± 0.15 ng/g and are slightly lower than concentrations reported by Atteia [1], by Batifol et al. [2], and by Wagenbach et al. [3] for precipitation samples from similar remote sites in Europe. Since concentrations of lead in the fresh snow samples were mainly in the lower pg/g range, the method to determine the isotopic ratios 207Pb/206Pb and 208Pb/206Pb had to be optimized. They could finally be determined with an average standard error of 0.14% within 12 min and a total sample consumption of 0.8 mL. The average ratios 207Pb/206Pb and 208Pb/206Pb were 0.875 and 2.117, respectively. These values are comparable to isotopic compositions of lead in aerosols collected in Western Europe [4] and are less radiogenic than predicted by Grousset et al. [5]. Our data indicate that, although lead emissions from traffic have decreased largely during the last 10 years, the contribution from this source in modern snow is still detectable and seems to be equal to the lead input from other anthropogenic sources (e.g. waste incineration, industry).
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0375-9474
    Keywords: Radioactivity
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The heaviest elements to have been chemically characterized are seaborgium (element 106), bohrium (element 107) and hassium (element 108). All three behave according to their respective positions in groups 6, 7 and 8 of the periodic table, which arranges elements according to their outermost ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Polluted air masses are characterized by high concentrations of oxidized nitrogen compounds which are involved in photochemical smog and ozone formation. The OH radical is a key species in these oxidation processes. The photolysis of nitrous acid (HNO2), in the morning, leads to the ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 384 (1996), S. 32-32 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR-Tetrafluoromethane (CF4), a potent greenhouse gas1 with an atmospheric life-time of at least 50,000 years (ref. 2), is believed to be of purely anthropogenic origin. Here we present evidence that about half the current atmospheric bur-den of CF4 has accumulated naturally from weak, probably ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0029-554X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...