Measurement of vitellogenin from rainbow trout by rocket immunoelectrophoresis: application to the kinetic analysis of estrogen stimulation in the male

1985 ◽  
Vol 63 (9) ◽  
pp. 982-987 ◽  
Author(s):  
Jean Louis Maitre ◽  
Catherine Le Guellec ◽  
Stephane Derrien ◽  
Martin Tenniswood ◽  
Yves Valotaire

The study of the seasonal regulation of vitellogenesis in rainbow trout (Salmo gairdneri) is hampered by two features of the system which are not seen in species such as Xenopus. First, it is impossible to sex immature trout by external appearance and, secondly, the quantitation of the very low levels of vitellogenin in previtellogenic serum is technically difficult and tedious. We describe the preparation of a specific, sensitive anti-vitellogenin antibody and the use of this antibody in a rocket immunoelectrophoresis system to measure serum vitellogenin. The sensitivity of the assay is such that, using only 2 μL of serum, it is possible to detect vitellogenin at levels of 10 μg/mL, making this assay extremely useful for selecting immature female trout for further studies on the basis of the presence of vitellogenin. Using this system we have also measured the response of individual male trout to stimulation with different levels of estradiol, and we have shown that it is possible to measure the stimulation of vitellogenin by estradiol levels equivalent to those seen during the previtellogenic phase of the reproductive cycle in females. This simple assay system thus alleviates two of the major hurdles in studying vitellogenesis in trout.


1968 ◽  
Vol 25 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Joseph B. Hunn ◽  
Richard A. Schoettger ◽  
Wayne A. Willford

Rainbow trout: (Salmo gairdneri) anesthetized in 100 mg/liter of M.S. 222 at 12 C excreted the drug in free and acetylated forms via the urine during a 24-hr recovery period in freshwater. Of the M.S. 222 excreted, 77–96% was acetylated. Blood levels of free drug in anesthetized trout approximated 75% of the anesthetic concentration, but the amount of acetylated M.S. 222 was relatively insignificant. The blood and urine were cleared of the two fractions of M.S. 222 in 8 and 24 hr respectively. Low levels of aromatic amines of natural origin occurred in blood and urine and were subtracted from measurements of M.S. 222. Intraperitoneal injections of 10–100 mg/kg of M.S. 222 did not induce anesthesia; however, the 24-hr pattern of drug excretion was similar to that observed after anesthesia by immersion. Only 15–21% of the injected dose was found in the urine, suggesting a second route of drug elimination.



1988 ◽  
Vol 45 (12) ◽  
pp. 2206-2215 ◽  
Author(s):  
Douglas J. Spry ◽  
Chris M. Wood

At a waterborne [Zn] of 1.9 mg∙L−1 in hard water (~1 mmol Ca∙L−1), Zn influx across an isolated, saline-perfused head preparation of rainbow trout (Salmo gairdneri) was about 1.5 nmol∙kg−1∙h−1 through the lamellar pathway and about 1 nmol∙kg−1∙h−1 through the filamental route. Flux rates came rapidly to steady state in both pathways. Trout preexposed to artificial soft water (~0.05 mmol Ca∙L−1) for 5 d showed differential stimulation of flux rates to about 42 and 5 nmol Zn∙kg−1∙h−1 through the lamellar and filamental pathways, respectively. Under these conditions, steady-state fluxes across the lamellae did not occur until 15–20 min after the start of perfusion. Preparations from hardwater-acclimated trout tested in soft water gave typical hardwater fluxes showing that these changes in influx were not simply due to acute exposure of the gill surface to low waterborne [Ca]. Influxes in softwater trout, studied over [Zn] from 0.4 to 7.5 mg Zn∙L−1, revealed a saturable, first-order uptake with apparent Jmax and Km of 150 nequiv∙kg−1∙h−1 and 1.5 mg Zn∙L−1 (23 μmol∙L−1), respectively. Because the apparent Km is in the toxic range, Zn is clearly not the primary substrate. Scanning electron micrography revealed hypertrophy and increased apical exposure of chloride cells; this stimulation, coupled with the increase in Zn influx, suggests that chloride cells may be the site of entry of Zn across the gill.



1981 ◽  
Vol 45 (1) ◽  
pp. 137-148 ◽  
Author(s):  
D. Knox ◽  
C. B. Cowey ◽  
J. W. Adron

1. Rainbow trout (Salmo gairdneri) of mean initial weight 35 g were given one of five experimental diets for 20 weeks. The diets contained (g/kg dry diet) 15 calcium, 10 phosphorus and graded levels of magnesium from 0.04 (diet no. 1) to 1.0 (diet no. 5). In a second experiment rainbow trout of mean initial weight 16 g were given one of six experimental diets for 20 weeks. The diets contained (g/kg dry diet): Ca (40), P (30) and levels of Mg from 0.06 (diet no. 6) to 2.0 (diet no. 11).2. In both experiments weight gains were lowest in those trout given diets containing the basal levels of Mg (diet no. 1 and diet no. 6) but increased with increasing dietary Mg concentration. In neither experiment was there any further increase in weight gain once the Mg concentration reached 0.25–0.5 g/kg dry diet; weight gain reached a plateau at this dietary Mg level.3. The following trends occurred in serum electrolyte concentrations as dietary Mg increased. Mg increased in both experiments, in Expt 2 it reached a maximum of 1 mmol/l when the diet containted 0.5 g Mg/kg and did not increase further; sodium was positively correlated in both experiments; potassium decreased and in Expt 2 reached a plateau minimum of 1.7 mmol/l at a dietary Mg concentration of 0.5 g/kg; Ca and P altered little in either experiment.4. In both experiments renal Ca concentrations were greatly increased in trout given diets lacking supplementary Mg; they fell to low levels (3–5 mmol/kg) when diets conained 0.15 g Mg/kg or more. Renal K and P concentrations were negatively correlated with dietary Mg in Expt 2; other electrolytes measured were not altered in concentration by the treatments used.5. Extracellular fluid volume (ECFV) of muscle was negatively correlated with dietary Mg. In Expt 2 it reached a minimal or normal value at 0.5 g Mg/kg diet and did not decease further. Muscle Mg concentration increased with diet Mg in both experiments and muscle K concentration was also correlated with diet Mg in Expt 2. These changes were related to the shift in muscle water. In Expt 1, P concentration was decreased with increasing diet Mg but in Expt 2 its concentration increased, these changes may have been connected with the three-fold difference in dietary P in the two experiments.6. By contrast with skeletal muscle, Mg levels in cardiac muscle increased at low dietary Mg intakes.7. Concentrations of electrolytes in liver did not alter with dietary treatments used.8. The results show that Mg requirement of rainbow trout is met by a diet containing 0.5 g Mg/kg diet.



1984 ◽  
Vol 41 (12) ◽  
pp. 1768-1773 ◽  
Author(s):  
S. F. Perry ◽  
P. Payan ◽  
J. P. Girard

Experiments were conducted using a saline-perfused trout (Salmo gairdneri) head preparation in an attempt to determine the origin of HCO3− involved in gill apical Cl−/HCO3− exchange, the possibilities being plasma CO2 or HCO3−. Initial results showed that branchial Cl− influx was stimulated both by increased perfusate [HCO3−] and Pco2. Subsequent experiments employing the chloride transport inhibitors, SITS and thiocyanate, indicated that stimulation of Cl− influx by HCO3− probably was due to gill hemodynamic alterations and not to increased entry of HCO3− into the gill epithelium. We conclude that CO2 entry into the gill epithelium from plasma and its subsequent hydration to HCO3− and H+, by carbonic anhydrase, is a major pathway by which HCQ3− for Cl−/HCO3− exchange is generated.



1984 ◽  
Vol 62 (8) ◽  
pp. 1495-1501 ◽  
Author(s):  
J. G. Eales ◽  
Shirley Shostak ◽  
Catherine G. Flood

The effects of the thiols DTT (dithiothreitol) and GSH (reduced glutathione) on hepatic in vitro and in vivo T4 (L-thyroxine) deiodination by rainbow trout held at 11 °C were studied. Hepatic deiodination increased progressively over the DTT range of 0.02–20 mM. GSH was less potent than DTT at low concentrations and strongly inhibited deiodination at high concentrations (> 1 mM). Hepatic deiodination was not increased by 1 mM NADPH or anaerobic conditions and was enhanced and not inhibited by the GSH inhibitor, diamide (2.5 mM), indicating that the low T4 deiodination in the absence of DTT is not due to endogenous GSH deficiency. Intraperitoneally injected GSH consistently increased plasma levels of 125I and [125I]-3,5,3′-triiodo-L-thyronine (T3) in fed or starved [125I]T4-injected trout, suggesting a GSH stimulation of extrahepatic T4 deiodination. However, injected GSH did not elevate plasma T3 concentrations. This was probably due to a demonstrated GSH stimulation of plasma T4 and T3 clearance. Force-fed GSH did not increase [125I]T4 deiodination. It is concluded that exogenous thiols can enhance T4 deiodination both in vitro and in vivo. However, availability of neither endogenous nor dietary GSH appears to regulate T4 deiodination under physiological conditions, including altered nutritional state.



1976 ◽  
Vol 33 (4) ◽  
pp. 666-675 ◽  
Author(s):  
Mark G. Pedersen ◽  
William K. Hershberger ◽  
Prince K. Zachariah ◽  
Mont R. Juchau

Six strains of rainbow trout (Salmo gairdneri), each geographically and genetically distinct, were compared in relation to their capacity for hepatic hydroxylation of aniline and benzo[a]pyrene, and reduction of p-nitrobenzoic acid to p-aminobenzoic acid, in vitro. The effects of 3-methylcholanthrene on stimulation of nitro reductase and aryl hydrocarbon hydroxylase were examined. For the three systems studied, a significant pattern was observed with respect to each strain’s capacity for metabolism. Induction experiments suggested that environment may influence gene expression. Enzyme kinetics and spectral properties were also examined, and mechanisms causing variability within and among strains were discussed.



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