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Increased serum and testicular androgen levels in F1 rats with lifetime exposure to soy isoflavones.
Reprod Toxicol. 2004 Jul; 18(5):677-85.RT

Abstract

The consequences of dietary soy isoflavones on serum and testicular androgen levels were examined in F1 male rats from a multigeneration study investigating the effects of diets varying in isoflavone content. Rats were fed either a soy-free casein based diet (AIN93G) or a diet in which alcohol-washed soy protein replaced casein as the protein source and to which increasing amounts of Novasoy, a commercially available isoflavone supplement were added. Analysis of these diets showed that the isoflavone content in each diet was 0 (diet 1; casein based control), 31.7 (diet 2; alcohol-washed soy-based diet control), 36.1 (diet 3), 74.5 (diet 4), 235.6 (diet 5) and 1046.6 (diet 6) mg total isoflavones/kg pelleted diet. The levels of isoflavones in diet 1 would represent a daily intake level of 0 mg isoflavones, diets 2 and 3 estimate a low soy-containing human diet (e.g. North American), diet 4 would correspond to Asian diets (e.g. Japanese) or adult humans taking isoflavone supplements, diet 5 approximates the isoflavone intake by babies fed soy based infant formula and diet 6 approximates fivefold the intake levels by babies or 10-fold the intake levels of adults consuming high isoflavone containing diets. Serum testosterone (T) from F1 male rats sacrificed on postnatal days (PND) 28, 70, 120, 240 and 360 were low at PND 28 (0.4 ng/ml), increased approximately five to sixfold at PND 70 (2.5-3.0 ng/ml) and thereafter declined to a steady state level of approximately 1 ng/ml by PND 120. However, rats on diets 5 and 6 demonstrated altered serum testosterone profiles such that at days 120, testosterone levels remained significantly elevated at approximately 3 ng/ml (P < 0.05). Serum dihydrotestosterone levels exhibited similar profiles and the levels in PND 120 rats on diet 5 or 6 were also significantly elevated (two to threefold, P < 0.05). The intra-testicular testosterone concentration in rats on diet 5 was also elevated at PND 120 compared with diet 1 (P < 0.05). These findings show that F1 male rats continuously exposed to a mixture of dietary soy isoflavones from conception onwards exhibit altered serum and testicular androgen profiles.

Authors+Show Affiliations

Reproductive Biology Unit, Departments of Cellular and Molecular Medicine and Obstetrics and Gynecology, University of Ottawa, Ottawa, ON, Canada.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

15219630

Citation

McVey, Mark J., et al. "Increased Serum and Testicular Androgen Levels in F1 Rats With Lifetime Exposure to Soy Isoflavones." Reproductive Toxicology (Elmsford, N.Y.), vol. 18, no. 5, 2004, pp. 677-85.
McVey MJ, Cooke GM, Curran IH. Increased serum and testicular androgen levels in F1 rats with lifetime exposure to soy isoflavones. Reprod Toxicol. 2004;18(5):677-85.
McVey, M. J., Cooke, G. M., & Curran, I. H. (2004). Increased serum and testicular androgen levels in F1 rats with lifetime exposure to soy isoflavones. Reproductive Toxicology (Elmsford, N.Y.), 18(5), 677-85.
McVey MJ, Cooke GM, Curran IH. Increased Serum and Testicular Androgen Levels in F1 Rats With Lifetime Exposure to Soy Isoflavones. Reprod Toxicol. 2004;18(5):677-85. PubMed PMID: 15219630.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Increased serum and testicular androgen levels in F1 rats with lifetime exposure to soy isoflavones. AU - McVey,Mark J, AU - Cooke,Gerard M, AU - Curran,Ivan H A, PY - 2003/12/02/received PY - 2004/03/30/revised PY - 2004/04/22/accepted PY - 2004/6/29/pubmed PY - 2005/1/8/medline PY - 2004/6/29/entrez SP - 677 EP - 85 JF - Reproductive toxicology (Elmsford, N.Y.) JO - Reprod. Toxicol. VL - 18 IS - 5 N2 - The consequences of dietary soy isoflavones on serum and testicular androgen levels were examined in F1 male rats from a multigeneration study investigating the effects of diets varying in isoflavone content. Rats were fed either a soy-free casein based diet (AIN93G) or a diet in which alcohol-washed soy protein replaced casein as the protein source and to which increasing amounts of Novasoy, a commercially available isoflavone supplement were added. Analysis of these diets showed that the isoflavone content in each diet was 0 (diet 1; casein based control), 31.7 (diet 2; alcohol-washed soy-based diet control), 36.1 (diet 3), 74.5 (diet 4), 235.6 (diet 5) and 1046.6 (diet 6) mg total isoflavones/kg pelleted diet. The levels of isoflavones in diet 1 would represent a daily intake level of 0 mg isoflavones, diets 2 and 3 estimate a low soy-containing human diet (e.g. North American), diet 4 would correspond to Asian diets (e.g. Japanese) or adult humans taking isoflavone supplements, diet 5 approximates the isoflavone intake by babies fed soy based infant formula and diet 6 approximates fivefold the intake levels by babies or 10-fold the intake levels of adults consuming high isoflavone containing diets. Serum testosterone (T) from F1 male rats sacrificed on postnatal days (PND) 28, 70, 120, 240 and 360 were low at PND 28 (0.4 ng/ml), increased approximately five to sixfold at PND 70 (2.5-3.0 ng/ml) and thereafter declined to a steady state level of approximately 1 ng/ml by PND 120. However, rats on diets 5 and 6 demonstrated altered serum testosterone profiles such that at days 120, testosterone levels remained significantly elevated at approximately 3 ng/ml (P < 0.05). Serum dihydrotestosterone levels exhibited similar profiles and the levels in PND 120 rats on diet 5 or 6 were also significantly elevated (two to threefold, P < 0.05). The intra-testicular testosterone concentration in rats on diet 5 was also elevated at PND 120 compared with diet 1 (P < 0.05). These findings show that F1 male rats continuously exposed to a mixture of dietary soy isoflavones from conception onwards exhibit altered serum and testicular androgen profiles. SN - 0890-6238 UR - https://www.unboundmedicine.com/medline/citation/15219630/Increased_serum_and_testicular_androgen_levels_in_F1_rats_with_lifetime_exposure_to_soy_isoflavones_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S089062380400070X DB - PRIME DP - Unbound Medicine ER -