The use of 17-hydroxyprogesterone as a biomarker in men seeking fertility

Strategies to increase testosterone in men seeking fertility
Kevin Y. Chu , Justin K. Achua , Ranjith Ramasamy


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ABSTRACT

The prevalence of testosterone deficiency is increasing in the adolescent and young adult male population. As the average paternal age rises, there is a significant population of men with hypogonadism seeking testosterone therapy wishing to achieve or maintain fertility potential. Identification of potential lifestyle modifications that may improve testosterone deficiency is one of the initial interventions of the holistic strategy in treatment. This is followed by drug therapy; however, traditional testosterone therapy acts as a contraceptive by suppressing the hypothalamus-pituitary-gonadal (HPG) axis and therefore cannot be used as a treatment strategy. A solution has been the off-label use of selective estrogen receptor modulators, human chorionic gonadotropin (hCG), and anastrozole inhibitors to treat hypogonadal symptoms while increasing intratesticular testosterone, a necessity for spermatogenesis. Recently, a novel therapy, Natesto intranasal testosterone gel, has been shown to increase serum testosterone levels while maintaining semen parameters. This is hypothesized to be because of its short-acting properties having a lesser effect on the HPG axis, in contrast to the long-acting properties of traditional testosterone therapy. It is important to differentiate hypogonadal men between those seeking to achieve or maintain fertility status because the drug therapy of choice differs. This can be accomplished by determining the levels of 17-hydroxyprogesterone (17-OHP) because it is a biomarker for intratesticular testosterone. Those with low 17-OHP may wish to initiate treatment with alternative therapies, whereas those with high 17-OHP may trial short-acting testosterone therapies. As the urologist’s armamentarium continues to increase, better strategies to increase testosterone levels in men seeking fertility can be achieved.





Introduction

Male hypogonadism is estimated to have a prevalence of 2.1% and 5.6% by the Massachusetts Male Aging Study and the European Male Aging Study, respectively.[1,2] A diagnosis of male hypogonadism is defined as a state of low serum testosterone (>300 ng/dL) and concurrent clinical symptoms that impact physical and mental health.[3] The symptoms are broad and vary depending on the age of onset and severity of testosterone deficiency. These symptoms include decreased libido, erectile dysfunction, infertility, low energy, low mood, depression, gynecomastia, decreased lean muscle mass, increased body fat gain, and osteoporosis.[3,4] Low serum testosterone has also been shown to have potential long-term negative effects on cardiovascular health, metabolism, and longevity.[5] Because the average paternal age has increased over time, and hypogonadism rates increase with age, the challenge of treating low testosterone while maintaining fertility status has become paramount.[6] Although testosterone deficiency was commonly thought to be a diagnosis in only older men, recent studies have started to show an increase in prevalence in younger men too.[7] This impacts the potential testosterone therapy plan because the patient’s desire for conception needs to be considered.

Testosterone deficiency in adolescents and young adult (AYA) men, defined as those between the ages of 15-39, has a prevalence of approximately 20%. In addition, studies have shown that total testosterone levels among AYA men have been declining over the past few decades. Although increasing obesity rates have shown to be an independent predictor of declining testosterone levels, Lokeshwar et al.[7] demonstrated a decline in total testosterone among AYA males despite controlling for confounders. AYA men diagnosed with hypogonadism present with initial symptoms of low energy and fatigue, in contrast to the complaints of decreased libido or erectile dysfunction in older men.[8]
Among this patient population, strategies to increase testosterone levels to address hypogonadal symptoms must be well thought out to maintain fertility status.





In this review, we have summarized the various therapies available for increasing testosterone levels in men seeking fertility. These therapies include selective estrogen receptor modulators, gonadotropins, aromatase inhibitors, and testosterone therapy. In addition, it is important to consider non-drug approaches to increase testosterone levels. This allows for a holistic approach to treating hypogonadism. Treating hypogonadism can be difficult for physicians, because inappropriate therapies, such as exogenous testosterone, will suppress spermatogenesis and impact future fertility. The physician and the patient must have a thoughtful discussion before initiating the treatment.






Drug Therapies for Testosterone Deficiency

Testosterone therapy (TT)

Alternative therapy: selective estrogen receptor modulators (SERMs)

Alternative therapy: gonadotropins

Alternative therapy: aromatase inhibitors (AIs)

Differentiating Treatment with Alternative Therapies versus Novel Testosterone Therapy

Non-drug Strategies for Testosterone Deficiency







Conclusion

Testosterone deficiency is a clinical problem that is increasing in prevalence among AYA. As the average paternal age increases, the hypogonadal population seeking to improve or maintain fertility gets larger. A holistic approach with counseling on lifestyle modifications is a must. Alternative therapies such as SERMs, hCG, or anastrozole inhibitors have been used off-label for treatment. Recent drug development of a short-acting testosterone formulation, Natesto, has been approved for testosterone therapy, and studies have shown maintenance of semen parameters with it. In addition, 17-OHP has been identified as a potential biomarker for intratesticular testosterone levels, which will allow for better counseling of patients on the appropriate treatment strategy. As the urologist’s armamentarium continues to increase, better strategies to increase testosterone levels in men seeking fertility can be achieved.
 
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Main Points:

Selective estrogen receptor modulators, hCG, and anastrozole inhibitors are used off-label to increase intratesticular testosterone, which is essential for spermatogenesis.

Short-acting testosterone preparations, such as Natesto intranasal gel, has been shown to increase serum testosterone levels while maintaining semen parameters in a clinical trial. The short-acting properties are hypothesized to have lesser effect on the hypothalamus-pituitary-gonadal (HPG) axis than traditional long-acting testosterone therapy.

17-OHP is a biomarker for intratesticular testosterone, and its levels can be used to differentiate between men with hypogonadism needing improvement versus those who need to maintain their semen parameters.
 
17-OHP is a biomarker for intratesticular testosterone, and its levels can be used to differentiate between men with hypogonadism needing improvement versus those who need to maintain their semen parameters.


 
Serum 17-hydroxyprogesterone (17-OHP) has emerged as a promising biomarker for estimating intratesticular testosterone (ITT) levels, offering a less invasive alternative to direct testicular sampling. Studies have shown that serum 17-OHP strongly correlates with ITT, particularly in men undergoing gonadotropin suppression and human chorionic gonadotropin (hCG) stimulation, with the strength of this correlation influenced by factors such as hCG dosage, testosterone administration route, and treatment duration.


Serum 17-OHP as Biomarker​


Serum 17-hydroxyprogesterone (17-OHP) demonstrates a robust correlation with intratesticular testosterone (ITT) levels, particularly in men undergoing gonadotropin suppression and human chorionic gonadotropin (hCG) stimulation12. This correlation is observed in both absolute concentrations and changes from baseline, with higher doses of hCG (500 IU every other day) significantly increasing both serum 17-OHP and ITT levels1. The strong association between serum 17-OHP and ITT suggests its potential as a reliable surrogate biomarker for estimating testicular testosterone production non-invasively, which could have significant implications for clinical research and the optimization of hormonal therapies in men with infertility due to hypogonadotropic hypogonadism123.



Factors Influencing 17-OHP Correlation​


Several key factors influence the correlation between serum 17-hydroxyprogesterone (17-OHP) and intratesticular testosterone (ITT):

  • hCG dosage: Higher doses (500 IU every other day) result in stronger correlations, while lower doses may lead to disproportionate increases in ITT compared to serum 17-OHP1.
  • Gonadotropin suppression: The correlation becomes significant only when endogenous gonadotropins are suppressed by exogenous testosterone2.
  • Treatment duration: The strongest correlation is typically observed at the end of treatment periods, with shorter durations (e.g., 3 weeks) showing robust responses to hCG stimulation12.
  • Baseline conditions: Initially, there is no significant correlation between serum 17-OHP and ITT before hormonal manipulation1.
These factors underscore the importance of carefully controlled treatment conditions when using serum 17-OHP as a biomarker for ITT in clinical research and practice.


Comparison with Other Biomarkers​


While serum 17-hydroxyprogesterone (17-OHP) has shown strong correlation with intratesticular testosterone (ITT), other potential biomarkers have been investigated:

  • Insulin-Like Factor 3 (INSL3) demonstrates high correlation with ITT during gonadotropin suppression and hCG stimulation, decreasing significantly with suppression and increasing dose-dependently with hCG1.
  • Androstenedione shows some correlation with ITT, but it is weaker than 17-OHP and less reliable across treatment contexts.
  • Dihydroepiandrosterone (DHEA) has not shown significant or consistent correlation with ITT, limiting its utility as a biomarker.
  • Inhibin B and Anti-Müllerian Hormone, produced by Sertoli cells, do not directly correlate with ITT but may provide complementary information about testicular function.
Among these, INSL3 emerges as a promising candidate alongside 17-OHP due to its high correlation with ITT and responsiveness to hCG stimulation, warranting further research to validate its clinical utility across diverse populations and treatment conditions.

Impact of Testosterone Treatments​


Exogenous testosterone administration significantly influences the relationship between serum 17-hydroxyprogesterone (17-OHP) and intratesticular testosterone (ITT). Long-acting formulations, such as intramuscular injections or subcutaneous pellets, cause a more pronounced decrease in serum 17-OHP compared to short-acting formulations like intranasal testosterone1. This difference is attributed to the prolonged suppression of luteinizing hormone (LH) with long-acting formulations, whereas short-acting formulations better preserve LH pulsatility and Leydig cell function1. The addition of human chorionic gonadotropin (hCG) to exogenous testosterone therapy restores Leydig cell stimulation, increasing both ITT and serum 17-OHP levels, with the correlation becoming strongest at higher hCG doses (e.g., 500 IU every other day)23.
 
Serum 17-hydroxyprogesterone (17-OHP) has emerged as a promising biomarker for evaluating intratesticular testosterone (ITT) and predicting the response to medical therapy in male infertility. Its clinical utility is particularly relevant in scenarios where improving spermatogenesis and semen quality is the therapeutic goal. Below is a summary of its utility and recommendations based on clinical scenarios:

Clinical Utility of Serum 17-OHP

  1. Marker for Intratesticular Testosterone (ITT):
    • ITT is critical for spermatogenesis, but its direct measurement requires invasive procedures such as testicular aspiration. Serum 17-OHP, an intermediate in testosterone biosynthesis, correlates strongly with ITT levels, offering a non-invasive alternative256.
    • Studies have shown that men receiving human chorionic gonadotropin (hCG) or clomiphene citrate (CC) experience increases in serum 17-OHP, reflecting improved ITT and spermatogenesis45.
  2. Predictor of Treatment Response:
    • Men with lower baseline serum 17-OHP levels (≤55ng dL
      ) are more likely to experience significant improvements in semen parameters, including total motile sperm count (TMSC), after treatment with CC or hCG14.
    • Conversely, men with higher baseline 17-OHP levels (>55ng dL
      ) may not show comparable improvements in semen quality14.
  3. Monitoring Therapeutic Progress:
    • Changes in serum 17-OHP during therapy can help monitor the effectiveness of treatments aimed at increasing ITT, such as hCG or CC therapy. This allows for a personalized approach to managing male infertility35.

Recommended Clinical Scenarios

  1. Hypogonadotropic Hypogonadism:
    • In men with secondary hypogonadism, where ITT is insufficient due to low gonadotropin stimulation, serum 17-OHP can guide therapy with hCG or CC and predict outcomes26.
  2. Idiopathic Infertility:
    • For men with idiopathic oligospermia and low testosterone, baseline serum 17-OHP can identify candidates likely to benefit from medical therapy aimed at improving ITT and spermatogenesis46.
  3. Azoospermia or Severe Oligospermia:
    • Men with azoospermia or severe oligospermia and low baseline 17-OHP are more likely to achieve motile sperm after treatment compared to those with normal baseline levels4.
  4. Patients on Testosterone Replacement Therapy (TRT):
    • Serum 17-OHP can help monitor ITT suppression caused by exogenous testosterone and guide adjunctive therapies like hCG to preserve fertility56.

Limitations and Considerations

  • While serum 17-OHP strongly correlates with ITT during gonadotropin stimulation, its sensitivity may vary depending on the dose of hCG used6.
  • The adoption of serum 17-OHP as a routine marker has been limited by the lack of standardized reference ranges and broader clinical validation23.
  • Single-institution studies with modest sample sizes highlight the need for larger, multicenter trials to confirm findings4.

Conclusion

Serum 17-OHP is a valuable tool for predicting and monitoring the response to medical therapy in male infertility. It provides a non-invasive means to assess ITT and personalize treatment strategies, particularly in men with hypogonadotropic hypogonadism or idiopathic infertility. However, further research is needed to standardize its use and expand its clinical adoption.

Citations:​

  1. Evaluation of a serum 17-hydroxyprogesterone as a predictor of semen parameter improvement in men undergoing medical treatment for infertility | Canadian Urological Association Journal
  2. Clinical utility of serum 17-hydroxyprogesterone as a marker for medical therapy for male infertility: recommendations based on clinical scenarios - International Journal of Impotence Research
  3. Clinical utility of serum 17-hydroxyprogesterone as a marker for medical therapy for male infertility: recommendations based on clinical scenarios - PubMed
  4. Evaluation of a serum 17-hydroxyprogesterone as a predictor of semen parameter improvement in men undergoing medical treatment for infertility - PMC
  5. https://www.auajournals.org/doi/pdf/10.1097/JU.0000000000001016
  6. Can serum 17-hydroxyprogesterone and insulin-like factor 3 be used as a marker for evaluation of intratesticular testosterone? - Patel - Translational Andrology and Urology
  7. 17-Hydroxyprogesterone: MedlinePlus Medical Test
  8. Can serum 17-hydroxy progesterone predict an improvement in semen parameters following micro-varicocelectomy? A prospective study | Archivio Italiano di Urologia e Andrologia
  9. https://www.semanticscholar.org/paper/63fa96b6ed11193b76a85bd9b54901b75c77d66c
 
Serum 17-hydroxyprogesterone (17-OHP) is increasingly recognized as a significant biomarker for predicting treatment success in male infertility, particularly in comparison to other markers such as follicle-stimulating hormone (FSH), testosterone, and emerging epigenetic or proteomic markers. Below is a detailed comparison of 17-OHP with other biomarkers based on their predictive utility for treatment outcomes.

Comparison of Serum 17-OHP to Other Biomarkers

MarkerUtility in Male InfertilityStrengthsLimitations
17-OHPPredicts intratesticular testosterone (ITT) levels and response to therapies like hCG or clomiphene citrate (CC).Non-invasive, directly correlates with ITT, useful for predicting semen quality improvement in low 17-OHP cases.Limited adoption due to lack of standardized thresholds and broader clinical validation349.
FSHIndicates spermatogenic activity and testicular function.Widely available; higher levels correlate with severe testicular damage or non-obstructive azoospermia (NOA).Limited sensitivity and specificity; does not directly reflect ITT or predict treatment response in all cases16.
TestosteroneReflects systemic androgen levels but not ITT.Useful for diagnosing hypogonadism.Does not correlate well with spermatogenesis or ITT; systemic levels may be normal while ITT is deficient36.
Epigenetic MarkersDNA methylation patterns in sperm predict responsiveness to FSH therapy.Emerging as a non-invasive predictor for treatment outcomes.Requires advanced testing; not yet widely available or validated for routine use2.
Proteomic MarkersProteins (e.g., LDHC, HSPA2) in seminal plasma indicate spermatogenic function.Non-invasive, promising for diagnosing NOA and predicting sperm retrieval success.Limited standardization; primarily useful in specific infertility subtypes like NOA57.

Key Findings on Serum 17-OHP

  1. Predictive Value for Treatment Success:
    • Low baseline serum 17-OHP (≤55ng dL
      ) has been shown to predict significant improvements in semen quality, including sperm concentration and total motile sperm count (TMSC), after medical therapy with hCG or CC49.
    • In patients undergoing exogenous FSH therapy, low serum 17-OHP levels (<1.18ng mL
      ) were associated with a doubling of sperm concentration and TMSC, highlighting its utility even in idiopathic infertility cases10.
  2. Correlation with Intratesticular Testosterone:
    • Unlike FSH or systemic testosterone, serum 17-OHP directly reflects ITT levels, which are critical for spermatogenesis. This makes it a superior marker for assessing the adequacy of gonadotropin-based therapies34.
  3. Clinical Scenarios:
    • Serum 17-OHP is particularly useful in secondary hypogonadism and idiopathic infertility where ITT needs to be optimized for spermatogenic recovery39.

Conclusion

Serum 17-OHP offers distinct advantages over traditional markers like FSH and testosterone by providing a direct reflection of ITT and predicting treatment responsiveness more accurately. While emerging biomarkers such as epigenetic and proteomic markers show promise, they are not yet widely available or validated for routine clinical use. Therefore, serum 17-OHP represents a practical and effective tool for guiding personalized treatment strategies in male infertility management.

Citations:​

  1. Seminal biomarkers for the evaluation of male infertility - PMC
  2. Sperm DNA Methylation Epimutation Biomarkers for Male Infertility and FSH Therapeutic Responsiveness - Scientific Reports
  3. Clinical utility of serum 17-hydroxyprogesterone as a marker for medical therapy for male infertility: recommendations based on clinical scenarios - International Journal of Impotence Research
  4. Evaluation of a serum 17-hydroxyprogesterone as a predictor of semen parameter improvement in men undergoing medical treatment for infertility - PMC
  5. Frontiers | Proteomic biomarkers in seminal plasma as predictors of reproductive potential in azoospermic men
  6. https://www.ijrcog.org/index.php/ijrcog/article/download/14010/8617/56118
  7. https://onlinelibrary.wiley.com/doi/10.1111/andr.13563
  8. NIH awards $3.4M to Wayne State University to investigate biomarkers for better reproductive success
  9. Evaluation of a serum 17-hydroxyprogesterone as a predictor of semen parameter improvement in men undergoing medical treatment for infertility | Canadian Urological Association Journal
  10. Predictive role of 17α-hydroxy-progesterone serum levels of response to follicle-stimulating hormone in patients with abnormal sperm parameters - PubMed
  11. Diagnosis and Treatment of Infertility in Men: AUA/ASRM Guideline - American Urological Association
  12. https://www.mdpi.com/2077-0383/13/11/3147
  13. https://pubmed.ncbi.nlm.nih.gov/26975492/
  14. https://www.nature.com/articles/srep15654
  15. https://www.mdpi.com/2227-9059/10/10/2599
  16. https://www.maleinfertilityguide.com/fsh-abnormalities
  17. https://www.auajournals.org/doi/pdf/10.1097/JU.0000000000001016
  18. https://www.mdpi.com/2077-0383/9/6/1785
  19. https://www.researchgate.net/public..._undergoing_medical_treatment_for_infertility
  20. https://www.ijrcog.org/index.php/ijrcog/article/view/14010
  21. https://pubmed.ncbi.nlm.nih.gov/32871440/
  22. https://pmc.ncbi.nlm.nih.gov/articles/PMC3652543/
  23. https://www.nature.com/articles/s41598-024-67910-0
  24. https://pmc.ncbi.nlm.nih.gov/articles/PMC2674872/
 

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