Neuropeptides in Human Reproduction

  • End date
    Aug 7, 2025
  • participants needed
  • sponsor
    Massachusetts General Hospital
Updated on 7 July 2022
body mass index
reproductive hormones
thyroid stimulating hormone
klinefelter syndrome
secondary hypogonadism
screening procedure
Accepts healthy volunteers


The investigators are seeking healthy volunteers and volunteers with reproductive disorders for the study of the role of dynorphin in the reproductive system. Dynorphin is a naturally occurring opioid hormone that is blocked by naloxone.

We hypothesize that naloxone, by blocking dynorphin, will stimulate production of GnRH and kisspeptin, 2 other naturally occurring reproductive hormones.

Condition Hypogonadotropic Hypogonadism
Treatment gonadotropin releasing hormone (GnRH), kisspeptin 112-121, naloxone
Clinical Study IdentifierNCT01952782
SponsorMassachusetts General Hospital
Last Modified on7 July 2022


Yes No Not Sure

Inclusion Criteria

Ages 21-40 (healthy men and regularly cycling women) OR ages 18-75 (men and women with hypogonadotropic hypogonadism (HH))
Normal blood pressure (systolic BP <140 mm Hg, diastolic BP <90 mm Hg)
White blood cell, platelets, prolactin, and thyroid stimulating hormone (TSH)within 90%-110% of laboratory reference range
Negative urine drug screen panel
For healthy men and healthy regularly cycling women: normal
For men and women with HH: No less than 0.5 gm/dL below the lower limit of the reference range for normal women
Blood urea nitrogen (BUN), creatinine, liver function tests not elevated
For healthy subjects: Normal reproductive function and history
For healthy subjects: Body Mass Index (BMI) 18.5-30kg/m2
For subjects with HH: All medical conditions stable and well controlled

Exclusion Criteria

History of medication reaction requiring emergency medical attention
Illicit drug use
Consumption of more than 10 alcoholic drinks per week
Difficulty with blood draws
Currently seeking fertility, breastfeeding, or pregnant
For healthy subjects: history of chronic disease and prescription medication use (with the exception of seasonal allergy medication)
For subjects with HH: prescription medications known to affect reproductive endocrine function except for those used to treat the subject's reproductive condition
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