scholarly journals Induction of capacitation and the acrosome reaction of boar spermatozoa by L-arginine and nitric oxide synthesis associated with the anion transport system

Reproduction ◽  
2002 ◽  
Vol 124 (6) ◽  
pp. 857-864
Author(s):  
H Funahashi
Keyword(s):  
Nitric Oxide ◽  
Transport System ◽  
Acrosome Reaction ◽  
Anion Transport ◽  
Nitric Oxide Synthesis ◽  
Anion Transport System ◽  
Boar Spermatozoa

scholarly journals Induction of capacitation and the acrosome reaction of boar spermatozoa by L-arginine and nitric oxide synthesis associated with the anion transport system

Reproduction ◽  
2002 ◽  
pp. 857-864 ◽  
Author(s):  
H Funahashi
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Acrosome Reaction ◽  
Fluorescein Isothiocyanate ◽  
Anion Transport ◽  
Nitric Oxide Synthesis ◽  
The Status ◽  
Anion Transport System ◽  
Synthase Inhibitor ◽  
Boar Spermatozoa

The aim of this study was to determine the effect of L-arginine on nitric oxide (NO) synthesis, capacitation and acrosome reaction of boar spermatozoa. Ejaculated boar spermatozoa were washed and then cultured in a bicarbonate:CO(2)-buffered medium, modified NCSU-37, for 2 h. At the end of the culture, the status of spermatozoa was determined. The presence of (0.1-2.0 mmol l(-1)) L-arginine in the culture medium induced an acrosome reaction as determined by fluorescein isothiocyanate-peanut agglutinin (FITC-PNA) and increased intracellular NO content, as quantified by a fluorescent indicator, diaminofluorescein-2 diacetate (DAF-2 DA). This stimulatory effect of L-arginine was neutralized by supplementation with an NO synthase inhibitor, N(omega)-nitro-L-arginine methyl ester (1 mmol l(-1)). However, the inactive enantiomorph, N(omega)-nitro-D-arginine methyl ester, did not affect the stimulatory effect of L-arginine. These results indicate that L-arginine induces an acrosome reaction through the NO signal pathway in boar spermatozoa. Furthermore, the stimulatory effect of L-arginine was inhibited in the presence of an anion transport inhibitor, 4-acetamido-4'-isothiocyano-stilbene-2,2'-disulphonic acid (SITS; 0.1 mmol l(-1)), whereas any responses of spermatozoa to caffeine were not inhibited by SITS. A stimulatory effect of L-arginine on capacitation and acrosome reaction of spermatozoa was also observed in modified NCSU37 medium by using a chlortetracycline fluorescence assay, but not in supplemented bicarbonate-free Tris-buffered medium. These results indicate that the presence of L-arginine induces nitric oxide synthesis and stimulates capacitation and acrosome reaction of boar spermatozoa only when active sperm anion transport is present as a result of bicarbonate supplementation.

scholarly journals Characteristics of bile salt uptake into skate hepatocytes

1994 ◽  
Vol 299 (3) ◽  
pp. 665-670 ◽  
Author(s):  
G Fricker ◽  
V Dubost ◽  
K Finsterwald ◽  
J L Boyer
Keyword(s):  
Substrate Specificity ◽  
Bile Salt ◽  
Transport System ◽  
Bile Salts ◽  
Organic Anion ◽  
Anion Transport ◽  
Organic Anion Transport ◽  
Salt Uptake ◽  
Anion Transport System ◽  
Alpha 7

The substrate specificity for the transporter that mediates the hepatic uptake of organic anions in freshly isolated hepatocytes of the elasmobranch little skate (Raja erinacea) was determined for bile salts and bile alcohols. The Na(+)-independent transport system exhibits a substrate specificity, which is different from the specificity of Na(+)-dependent bile salt transport in mammals. Unconjugated and conjugated di- and tri-hydroxylated bile salts inhibit uptake of cholyltaurine and cholate competitively. Inhibition is significantly greater with unconjugated as opposed to glycine- or taurine-conjugated bile salts. However, the number of hydroxyl groups in the steroid moiety of the bile salts has only minor influences on the inhibition by the unconjugated bile salts. Since the transport system seems to represent an archaic organic-anion transport system, other anions, such as dicarboxylates, amino acids and sulphate, were also tested, but had no inhibitory effect on bile salt uptake. To clarify whether bile alcohols, the physiological solutes in skate bile, share this transport system, cholyltaurine transport was studied after addition of 5 beta-cholestane-3 beta,5 alpha,6 beta-triol, 5 alpha-cholestan-3 beta-ol and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol. These bile alcohols inhibit cholyltaurine uptake non-competitively. In contrast, uptake of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol, which is Na(+)-independent, is not inhibited by cholyltaurine. The findings further characterize a Na(+)-independent organic-anion transport system in skate liver cells, which is not shared by bile alcohols and has preference for unconjugated lipophilic bile salts.

Kinetics of reversible DIDS inhibition of chloride self exchange in human erythrocytes

1989 ◽  
Vol 257 (4) ◽  
pp. C601-C606 ◽  
Author(s):  
T. Janas ◽  
P. J. Bjerrum ◽  
J. Brahm ◽  
J. O. Wieth
Keyword(s):  
Transport System ◽  
Time Course ◽  
Order Rate Constant ◽  
Anion Transport ◽  
Disulfonic Acid ◽  
Reversible Inhibitor ◽  
Apparent Dissociation Constant ◽  
Anion Transport System ◽  
Relative Change ◽  
Kinetics Of

The capnophorin (band 3)-mediated chloride self exchange flux in intact erythrocytes and in resealed erythrocyte ghosts was determined at pH 7.3 by measuring the unidirectional efflux of 36Cl-. The time-dependent irreversible inactivation of the anion transport system by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) was measured as the relative change of the unidirectional 36Cl efflux rate. The rate of covalent DIDS binding under conditions of excess DIDS in solution that ensure a complete irreversible inhibition followed an exponential time course with a rate coefficient Kcov (min-1). The Arrhenius activation enthalpy of Kcov was constant, 114 kJ/mol, at 0-38 degrees C. At 38 and 0 degrees C, Kcov was 0.5 min-1 [half time (T1/2) = ln2/Kcov = 1.3 min] and 0.004 min-1 (T1/2 = 178 min), respectively. The slow irreversible DIDS binding to the anion transport system at 0 degrees C allows a determination of the kinetics of the reversible DIDS reaction. The pseudo first-order rate constant for binding, kon, was 3.5 X 10(5) (M.s)-1. The apparent dissociation constant, KD, determined from the steady-state binding to the erythrocyte membrane was 3.1 X 10(-8) M at an equal internal and external Cl- concentration of 165 mM (0 degrees C). The value of KD shows that DIDS is the most efficient reversible inhibitor among the stilbene derivatives so far studied. Maximum reversible inhibition by DIDS was obtained by binding of a minimum of approximately 10(6) molecules/cell membrane. The number is similar to that obtained from studies of irreversible DIDS binding.

ATP-dependent transport of beta-estradiol 17-(beta-D-glucuronide) in rat canalicular membrane vesicles

1996 ◽  
Vol 271 (5) ◽  
pp. G791-G798
Author(s):  
M. Vore ◽  
T. Hoffman ◽  
M. Gosland
Keyword(s):  
Bile Acid ◽  
Transport System ◽  
Organic Anion ◽  
Membrane Vesicles ◽  
Anion Transport ◽  
Organic Anion Transport ◽  
Canalicular Membrane ◽  
P Glycoprotein ◽  
Anion Transport System ◽  
Dependent Transport

The ATP-dependent transport of beta-estradiol 17-(beta-D-glucuronide) (E217G), a cholestatic metabolite of estradiol, was investigated in rat liver canalicular membrane vesicles. ATP-dependent transport was dependent on time and temperature and occurred into an osmotically sensitive space; kinetic analysis indicated a saturable transport system (Michaelis-Menten constant value, 75 microM; maximum transport rate, 598 pmol.min-1.mg protein-1). The steroid conjugates estradiol glucuronide, estriol 3-glucuronide, estriol 16 alpha-glucuronide, testosterone glucuronide, and the three-sulfate conjugate of 17G were effective inhibitors of transport. Bromosulfophthalein, S-(2,4-dinitrophenyl)glutathione, and glutathione disulfide, all substrates of the canalicular ATP-dependent non-bile acid organic anion transport system, were also effective inhibitors, whereas taurocholate had no effect on transport. Conversely, E217G inhibited the ATP-dependent transport of S-(2,4-dinitrophenyl)glutathione. Daunorubicin, vinblastine, etoposide, cyclosporin, and PSC-833, substrates/modulators of P-glycoprotein, were also potent inhibitors of E217G transport, and E217G competitively inhibited the ATP-dependent transport of daunorubicin. C219, a monoclonal antibody against P-glycoprotein, inhibited ATP-dependent transport of E217G and daunorubicin but not of taurocholate or S-(2,4-dinitrophenyl)glutathione. These data indicate that E217G is substrate of both the non-bile acid organic anion transport system and P-glycoprotein but not of the ATP-dependent bile acid transport system in canalicular membranes.

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