Metabolic Fate of Diethylstilbestrol Implanted in the Ear of Steers

Pw, Aschbacher; Ej, Thacker; Ts, Rumsey

doi:10.2527/jas1975.403530x

Cited by 21 publications

(10 citation statements)

References 11 publications

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“…This lack of difference in recovery is due to the quantitative enzymatic hydrolysis of the glucuronides, since DES-MG was not extractable without hydrolysis. The measurement of free DES as well as its glucuronides is important because most of the total DES is bound as glucuronides, as was found in this present work as well as by Hoffmann and Laschutza (1980), , and Aschbacher et al (1975). In spite of this, neither Hoffmann and Laschutza (1980) nor Vogt (1980) documented, for their methods, equal recovery and measurement of free DES and its glucuronides; both reports only coincidently describe provisions for measurement of the glucuronides.…”

Section: Resultsmentioning

confidence: 48%

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Radioimmunoassay for diethylstilbestrol and the monoglucuronide metabolite in bovine liver

Gridley¹,

Allen²,

Shimoda³

1983

J. Agric. Food Chem.

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The complex matrix in liver causes difficulties in development of a radioimmunoassay (RIA) to quantify compounds bound in liver. An RIA method was developed for diethylstilbestrol (DES) in bovine liver and employs a purification procedure to circumvent these problems; the procedure includes liquid-liquid partitioning, Sephadex LH-20 chromatography, and quantitative enzymatic hydrolysis of the principal metabolite, DES glucuronide. Assay background due to liver matrix was 0.05 ppb (l/109). Average recovery of both DES and its monoglucuronide from fortified liver was 43% by RIA. Tritiated DES used as an internal standard had a higher apparent recovery (67.7%) by liquid scintillation counting. With an in vivo contaminated liver, accuracy was confirmed by a gas chromatography-mass spectrometry method. By repeating the extraction and RIA without enzymatic hydrolysis on this same liver, the free DES was calculated to be 7.8%. The limit of determination for this method with 95% confidence limits is 0.3 ppb.The application of radioimmunoassay (RIA) to drug residue analysis in animal tissues has been limited despite the proven sensitivity and specificity of RIA below the parts per billion (ppb, 1/109) range in biological fluids (Hoffmann, 1978). Complex tissues such as liver necessitate involved purification procedures. Hoffmann (1978) developed such purification procedures with RIA for both natural and synthetic steroids in muscle, liver, kidney, and fat.Diethylstilbestrol (DES) is difficult to quantitate below 1.0 ppb in bovine liver, which is among the last tissues to contain DES after cattle are withdrawn from the drug (Donoho et al., 1973; Aschbacher, 1976). Methods to measure DES in bovine liver include gas chromatography (GC) (Donoho et al., 1973), GC with mass spectrometry (GC-MS) (Day et al., 1975), and liquid chromatography (Kenyhercz and Kissinger, 1978), but quantitation below 1.0 ppb has not been documented for any of these methods.RIA is capable of greater sensitivity.Several researchers have developed RIA techniques for DES (Hoffmann, 1978;Gutierrez-Cernosek and Cernosek, 1977;Richoubac et al., 1977), but none was suitable for use with liver. Hoffmann andLaschutza (1980) and Vogt (1980) developed assays with extensive purification procedures for DES in bovine tissues, including liver; Hoffmann and Laschutza used both silica gel chromatography and liquid-liquid partition while Vogt relied entirely on liquid-liquid partition.In this study, we investigated the use of a simplified purification procedure combined with RIA for detecting and quantifying DES in bovine liver. The method developed was simpler and easier to perform than the above RIA methods. and was previously described (Gutierrez-Cernosek and Cernosek, 1977). The antigenic conjugate was prepared by the method of Rombauts et al. (1973) in which one phenolic group is covalently bonded through an ether linkage to the free amines of bovine serum albumin. The second antibody was lyophilized anti-rabbit y-globulin goat serum obtained from Micromedic ...

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Section: Resultsmentioning

confidence: 48%

“…Our method may be adaptable to measuring DES in these tissues as well as in liver. Because of high proportions of free DES in feces (Aschbacher et al, 1975), the method might be implemented for use with feces without enzymatic hydrolysis.…”

Section: Resultsmentioning

confidence: 99%

Radioimmunoassay for diethylstilbestrol and the monoglucuronide metabolite in bovine liver

Gridley¹,

Allen²,

Shimoda³

1983

J. Agric. Food Chem.

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“…The lower limit of detection in this work was 0.1 ppb based on 100 g of tissue. In other studies the residues of anabolic agents found by RIA techniques (see Pottier, Busigny & Grandadam, 1975;Aschbacher, Thacker & Rumsey, 1975;Hoffmann, 1978) were approximately 1-10 ppb in urine and <1 ppb in edible tissues. A more reliable and sensitive method is clearly required for the determination of zeranol in animal tissues.…”

Section: Introductionmentioning

confidence: 78%

Radioimmunoassay of the anabolic agent zeranol I. Preparation and properties of a specific antibody to zeranol

Dixon

1980

Vet Pharm & Therapeutics

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A highly specific antibody has been raised in sheep to an antigen prepared by coupling zeranol hemisuccinate to bovine serum albumin. An assay procedure is described and has been used to measure the cross‐reactivity of the antiserum, and evaluate the sensitivity of the assay method. The only compounds which reacted with the antibody were zeranol 100%, zearalanone 100%, zearalenone 19% and zearalenol 19%. The sensitivity of the assay procedure allows the determination of zeranol and/or its main metabolite zearalanone between 100 and 1000 pg.

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“…In terms of the residue curve, figure 8 shows how the use of implants reduces residue load. The generalized curves are based on labeled metabolism studies of Rumsey et al (1975aRumsey et al ( , 1975b and Aschbacher et al (1975). The darker lines project unmeasurable residue at 120 d and show that if DES is fed during a 120-d period (90-d treatment and 30-d withdrawal), residue load before withdrawal in liver tissue is approximately 17 ppb.…”

Section: Residue Curvementioning

confidence: 99%

“…Comparison of residue curves for oral and implanted diethylstilbestrol. Oral curve is based on data of Rumsey et al (1975a) and the light (---) implant curve is based on data of Aschbacher et al (1975) and Rumsey et al (1975b). The dark (--) implant curve represents an idealized curve.…”

Section: Residue Curvementioning

confidence: 99%

Experimental Approaches to Studying Metabolic Fate of Xenobiotics in Food Animals

Rumsey¹

1983

Journal of Animal Science

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The use of agricultural chemicals is an important aspect of animal production. Animal scientists have played an active and varied role in the recent and rapidly developed use of these chemicals. Although approval to use agricultural chemicals has always been based on both efficacy and end point residues, increased consumer concerns during the past one and one-half decades about the safety of these chemicals have caused greater awareness for the latter. In this regard, emphasis on the total residue curve of an agricultural chemical should serve as a tool that will help optimize dose rate on one hand and minimize end point residues on the other hand. Selection against lipophilic materials has resulted in a marked reduction in residue load. However, problems with lipophilic residues still exist, and knowledge about how to prevent or manage these residues in animals as well as fundamental knowledge about their absorption is needed. Continued emphasis on reducing residue load of hydrophilic chemicals through the use of devices such as implants, boluses and ear tags should have high priority as should research on the absorption and excretion mechanisms of these chemicals. There are two important areas of research that are needed to help us deal with end point residues in the future. One is better understanding of the toxicology of end point residues so we can move away from the concept of zero tolerance toward basing all of our guidelines for the use of a chemical on biological principles. The other is better understanding of the specific mode of action of the chemicals we use, which will permit more refined management of agricultural chemicals and a further assurance of safety.

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Metabolic Fate of Diethylstilbestrol Implanted in the Ear of Steers

Cited by 21 publications

References 11 publications

Radioimmunoassay for diethylstilbestrol and the monoglucuronide metabolite in bovine liver

Radioimmunoassay for diethylstilbestrol and the monoglucuronide metabolite in bovine liver

Radioimmunoassay of the anabolic agent zeranol I. Preparation and properties of a specific antibody to zeranol

Experimental Approaches to Studying Metabolic Fate of Xenobiotics in Food Animals

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