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RETRACTED ARTICLE: Effects of chronic treatment with the eNOS stimulator Impaza on penis length and sexual behaviors in rats with a high baseline of sexual activity

23 June 2020 Editor's Note: This article has been retracted. Please see the retraction notice for more detail: https://www.nature.com/articles/s41443-020-0321-x

21 May 2020 Editor's Note: Concerns have been raised about the scientific validity of this study (Chu et al., 2013). Further editorial action will be taken as appropriate once the investigation into the concerns is complete and all parties have been given an opportunity to respond in full.

A Retraction to this article was published on 23 June 2020

This article has been updated

Abstract

Endothelial nitric oxide synthase (eNOS) has an important role in erection, and it also affects aspects of sexual behavior. In this experiment, we determined whether a compound enhancing the activity of eNOS, Impaza, could stimulate any aspect of sexual behavior and increase penis length in rats with a high baseline of sexual activity. For comparison, the PDE5 inhibitor sildenafil was included. Male rats were orally treated with Impaza or sildenafil for 28 days. Impaza (3 ml kg−1) was given daily while sildenafil (3 mg kg−1) was given twice weekly. Tests for sexual incentive motivation and copulatory behavior were performed just before drug treatment and at days 7, 14 and 28 of treatment. In addition, the length of the protruding penis at mount, intromission and ejaculation was measured. Impaza but not sildenafil increased penis length at mount after 14 and 28 days of treatment. The compounds failed to modify sexual incentive motivation or copulatory behavior. It is suggested that Impaza enhanced intracavernous pressure, as such a pressure increase is the most likely explanation for enhanced penis length at mount. This effect, together with an absence of motivational actions, suggests that Impaza may be the most valuable treatment for erectile dysfunction.

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Change history

  • 21 May 2020

    Editor's Note: Concerns have been raised about the scientific validity of this study (Chu et al., 2013). Further editorial action will be taken as appropriate once the investigation into the concerns is complete and all parties have been given an opportunity to respond in full.

  • 23 June 2020

    Editor's Note: This article has been retracted. Please see the retraction notice for more detail: https://www.nature.com/articles/s41443-020-0321-x

  • 23 June 2020

    A Correction to this paper has been published: https://doi.org/10.1038/s41443-020-0321-x

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Acknowledgements

This study was financed by OOO “NPF “Materia Medica Holding”. Technical assistance was provided by Stig Rune Olsen, Ragnhild Osnes and Carina Sørensen.

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Correspondence to A Ågmo.

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Competing interests

ESZ (Research Associate), JLD (Head of Preclinical Development), IAK (Senior Research Associate), SAS (Chief Scientific Officer) have paid positions in OOO “NPF “Materia Medica Holding”, OIE is the General Director and the owner of the company above mentioned. XC and AÅ are employees of the University of Tromsø and have no financial interests in OOO “NPF “Materia Medica Holding”.

Additional information

The Editor has retracted this article because there are concerns about the scientific validity of the study. Specifically, the reagent is diluted beyond the point to which any active molecules are expected to be present and there is no molecular analysis to support the presence of molecules at these dilutions. These concerns have caused the Editor to lose faith in the reliability of the findings. All authors disagree with this retraction.

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Chu, X., Zhavbert, E., Dugina, J. et al. RETRACTED ARTICLE: Effects of chronic treatment with the eNOS stimulator Impaza on penis length and sexual behaviors in rats with a high baseline of sexual activity. Int J Impot Res 26, 35–40 (2014). https://doi.org/10.1038/ijir.2013.12

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