Kisspeptin to Quantify GnRH Neuronal Function in Health and Disease

The objective of this protocol is to use a case-control paradigm to compare the response to an intravenous administration of kisspeptin in individuals with and without post-covid-19 syndrome. The study subjects will receive a single bolus of kisspeptin.

Inclusion Criteria * Female (ages 18-45 years) or Male (ages 18-60 years) * No current or recent use of a medication (including hormonal replacement) that, in the opinion of a study investigator, can modulate the reproductive axis or willing to complete an appropriate washout for that particular medication and its method of administration * For women, negative serum hCG pregnancy test * For cases, diagnosis of post-covid-19 syndrome * For controls, history of prior covid infection but no diagnosis of post-covid-19 syndrome Exclusion Criteria * Any condition (medical, mental, or behavioral) that, in the opinion of a study investigator, would likely interfere with participation in/completion of the protocol or the interpretation of results * Active use of illicit drugs (not including marijuana) * For women, * Pregnant * Trying to become pregnant during protocol participation * Breast feeding * Surgical or natural menopause