Effects of the androgenic growth promoter 17‐β‐trenbolone on fecundity and reproductive endocrinology of the fathead minnow

Trenbolone acetate is a synthetic steroid that is extensively used in the United States as a growth promoter in beef cattle. The acetate is administered to livestock via slow-release implants; some is converted by the animal to 17-beta-trenbolone, a relatively potent androgen receptor agonist in mammalian systems. Recent studies indicate that excreted 17-beta-trenbolone is comparatively stable in animal waste, suggesting the potential for exposure to aquatic animals via direct discharge, runoff, or both. However, little is known concerning the toxicity of trenbolone to fish. Our goal was to assess the effects of 17-beta-trenbolone on reproductive endocrinology of the fathead minnow (Pimephales promelas). An in vitro competitive binding study with the fathead minnow androgen receptor demonstrated that 17-beta-trenbolone had a higher affinity for the receptor than that of the endogenous ligand, testosterone. Male and female fish were exposed for 21 d to nominal (target) concentrations of 17-beta-trenbolone ranging from 0.005 to 50 microg/L. Fecundity of the fish was significantly reduced by exposure to measured test concentrations > or = 0.027 microg/ L. The 17-beta-trenbolone was clearly androgenic in vivo at these concentrations, as evidenced by the de novo production in females of dorsal (nuptial) tubercles, structures normally present only on the heads of mature males. Plasma steroid (testosterone and beta-estradiol) and vitellogenin concentrations in the females all were significantly reduced by exposure to 17-beta-trenbolone. The 17-beta-trenbolone also altered reproductive physiology of male fathead minnows, albeit at concentrations much higher than those producing effects in females. Males exposed to 17-beta-trenbolone at 41 microg/L (measured) exhibited decreased plasma concentrations of 11-ketotestosterone and increased concentrations of beta-estradiol and vitellogenin. Overall, our studies indicate that 17-beta-trenbolone is a potent androgen and reproductive toxicant in fish. Given the widespread use of trenbolone acetate as a growth promoter, and relative stability of its metabolites in animal wastes, further studies are warranted to assess potential ecological risk.

[1]  R. L. Guével,et al.  Assessment of oestrogenic potency of chemicals used as growth promoter by in-vitro methods , 2001 .

[2]  J. Roche,et al.  4 – THE EFFECTS OF STEROID HORMONES AND XENOBIOTICS ON GROWTH OF FARM ANIMALS , 1986 .

[3]  E. M. de Groene,et al.  Development of an androgen reporter gene assay (AR-LUX) utilizing a human cell line with an endogenously regulated androgen receptor. , 2001, Analytical biochemistry.

[4]  Gerald T Ankley,et al.  Evaluation of the aromatase inhibitor fadrozole in a short-term reproduction assay with the fathead minnow (Pimephales promelas). , 2002, Toxicological sciences : an official journal of the Society of Toxicology.

[5]  L. Folmar,et al.  Vitellogenin induction and reduced serum testosterone concentrations in feral male carp (Cyprinus carpio) captured near a major metropolitan sewage treatment plant. , 1996, Environmental health perspectives.

[6]  Metabolism of Anabolic-Androgenic Steroids , 1991 .

[7]  H. Meyer.  Biochemistry and physiology of anabolic hormones used for improvement of meat production , 2001 .

[8]  J. Sumpter,et al.  Estrogenic Effects of Effluents from Sewage Treatment Works , 1994 .

[9]  G. Ankley,et al.  Masculinization of female mosquitofish in Kraft mill effluent-contaminated Fenholloway River water is associated with androgen receptor agonist activity. , 2001, Toxicological sciences : an official journal of the Society of Toxicology.

[10]  J. R. Morrison,et al.  Reproductive characteristics of adult channel catfish treated with trenbolone acetate during the phenocritical period of sex differentiation , 2000 .

[11]  B. Hales,et al.  Effect of estradiol-filled polydimethylsiloxane subdermal implants in adult male rats on the reproductive system, fertility, and progeny outcome. , 1987, Biology of reproduction.

[12]  Nancy D. Denslow,et al.  Overview of a workshop on screening methods for detecting potential (anti‐) estrogenic/androgenic chemicals in wildlife , 1998 .

[13]  B. Borg.  Androgens in teleost fishes , 1994 .

[14]  Pharmacological and endocrinological studies on anabolic agents. , 1976, Environmental quality and safety. Supplement.

[15]  J. Furr,et al.  Effects of environmental antiandrogens on reproductive development in experimental animals , 2001, Human reproduction update.

[16]  E. Thurman,et al.  Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-2000: a national reconnaissance. , 2002, Environmental science & technology.

[17]  H. Sauerwein,et al.  Characterisation of the affinity of different anabolics and synthetic hormones to the human androgen receptor, human sex hormone binding globulin and to the bovine progestin receptor , 2000, APMIS : acta pathologica, microbiologica, et immunologica Scandinavica.

[18]  E. Thurman,et al.  Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-2000: a national reconnaissance. , 2002 .

[19]  J. R. Morrison,et al.  Efficacy of Trenbolone Acetate in Sex Inversion of the Blue Tilapia Oreochromis aureus , 1996 .

[20]  G. Ankley,et al.  Fathead minnow vitellogenin: Complementary DNA sequence and messenger RNA and protein expression after 17β‐estradiol treatment , 2000 .

[21]  D. G. Joakim Larsson,et al.  More male fish embryos near a pulp mill , 2000 .

[22]  J. McLachlan,et al.  Fathead minnow (Pimephales promelas) vitellogenin: purification, characterization and quantitative immunoassay for the detection of estrogenic compounds. , 1999, Comparative biochemistry and physiology. Part C, Pharmacology, toxicology & endocrinology.

[23]  L. Gray,et al.  Evaluation of androstenedione as an androgenic component of river water downstream of a pulp and paper mill effluent , 2002, Environmental toxicology and chemistry.

[24]  H. Meyer,et al.  The fate of trenbolone acetate and melengestrol acetate after application as growth promoters in cattle: environmental studies. , 2001, Environmental health perspectives.

[25]  Vickie S Wilson,et al.  In vitro and in vivo effects of 17beta-trenbolone: a feedlot effluent contaminant. , 2002, Toxicological sciences : an official journal of the Society of Toxicology.

[26]  D. Kolpin,et al.  Pharmaceuticals, Hormones, and Other Organic Wastewater Contaminants in U.S. Streams , 2005 .

[27]  M. Pettersson,et al.  ETHINYLOESTRADIOL - AN UNDESIRED FISH CONTRACEPTIVE , 1999 .

[28]  K. Ryan,et al.  Phylogenetic distribution of aromatase and other androgen-converting enzymes in the central nervous system. , 1978, Endocrinology.

[29]  J. Raloff.  Hormones: Here's the Beef Environmental concerns reemerge over steroids given to livestock , 2002 .

[30]  Edwin J. Routledge,et al.  Identification of Estrogenic Chemicals in STW Effluent. 2. In Vivo Responses in Trout and Roach , 1998 .

[31]  Ana M Soto,et al.  Endocrine-disrupting effects of cattle feedlot effluent on an aquatic sentinel species, the fathead minnow. , 2003, Environmental health perspectives.

[32]  Edwin J. Routledge,et al.  Identification of Estrogenic Chemicals in STW Effluent. 1. Chemical Fractionation and in Vitro Biological Screening , 1998 .

[33]  R. J. Heitzman,et al.  Differences in the biotransformation of a 17 beta-hydroxylated steroid, trenbolone acetate, in rat and cow. , 1981, Xenobiotica; the fate of foreign compounds in biological systems.

[34]  J. A. Kemppainen,et al.  Identification of androstenedione in a river containing paper mill effluent , 2001, Environmental toxicology and chemistry.

[35]  J. Sumpter,et al.  Increase of Plasma Vitellogenin Concentration in Rainbow Trout (Oncorhynchus mykiss) Exposed to Effluents from Oil Refinery Treatment Works and Municipal Sewage , 1997, Bulletin of environmental contamination and toxicology.

[36]  G. Ankley,et al.  Description and evaluation of a short‐term reproduction test with the fathead minnow (Pimephales promelas) , 2001, Environmental toxicology and chemistry.

[37]  T. Steger-Hartmann,et al.  Morphological sex reversal upon short-term exposure to endocrine modulators in juvenile fathead minnow (Pimephales promelas). , 2002, Toxicology letters.

[38]  P. Mazik,et al.  Masculinization of Channel Catfish Ictalurus punctatus by Oral Administration of Trenbolone Acetate , 1995 .

[39]  C. Desjardins,et al.  Interactions of testosterone and estradiol-17 beta on the reproductive tract of the male rat. , 1979, Biology of reproduction.

[40]  G. Ankley,et al.  Aspects of basic reproductive biology and endocrinology in the fathead minnow (Pimephales promelas). , 2001, Comparative biochemistry and physiology. Toxicology & pharmacology : CBP.

[41]  H. Meyer.  Biochemistry and physiology of anabolic hormones used for improvement of meat production , 2001, APMIS : acta pathologica, microbiologica, et immunologica Scandinavica.