The goal of this study is to evaluate the effects of opioid antagonists on the hypothalamic-pituitary-gonadal axis in subjects with hypogonadotropic hypogonadism (HH).

Assignment: Each study subject will serve as their own control.

Delivery of Interventions:

• Prior to the study visit, subjects will undergo a review of their medical history and screening laboratories.

• During the study, the subjects will undergo the following:

  • Undergo q10 min blood sampling for 3 hours
  • Receive a naloxone bolus at the midpoint of q10 min sampling

Inclusion

• Male
• Age 18-75 years
• Confirmed diagnosis of hypogonadotropic hypogonadism (low testosterone)
• All medical conditions stable
• Normal blood pressure (systolic BP < 140 mm Hg, diastolic < 90 mm Hg)
• Negative urine drug screening panel
• Hemoglobin
• Men on adequate testosterone replacement therapy: normal male reference range
• Men off testosterone replacement therapy: no lower than 0.5 gm/dL below the lower limit of the reference range for normal women

Exclusion

• Any condition (medical, mental, or behavioral) that, in the opinion of a study investigator, would likely interfere with participation in/completion of the protocol
• Current or recent use of a medication (including hormonal replacement) that, in the opinion of a study investigator, can modulate the reproductive axis and, if applicable, unwilling to complete an appropriate washout for that particular medication and its method of administration
• Current or recent use of a medication that affects the opioid pathway
• Active illicit drug use

From time of study consent until removal from study participation (approximately 5 weeks).

All participants were asked about new health symptoms at each visit.