Steady-State Feedback Actions of Testosterone on Luteinizing Hormone Secretion in Young and Older Men

Mayo Clinic

Status and phase: Completed; Phase 1

Conditions: Hypogonadism

Treatments: Drug: Ketoconazole, Dexamethesone, Androgel,GnRH

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT00431197

Minn # 22270

344-03

Details and patient eligibility

About

This study is being done to learn how the male hormone , testosterone, affects pituitary hormones in younger and older men. The pituitary is a gland in the brain that secretes hormones, some of which normally control growth and fertility.

Full description

Concentrations of bioavailable testosterone decline by 1.0-1.5% annually as men age. Reduced systemic testosterone availability is associated with decreased muscle mass, strength and aerobic capacity, decreased bone-mineral density and increased risk of hip fracture, waning sexual interest, inpaired spatial cognition and increased risk of visceral obesity, impaired glucose tolerance and coronary artery disease. Luteinizing hormone (LH) secretion often fails in healthy older individuals. In addition, aging is marked by an acceleration of LH pulse frequency, loss of high-amplitude LH pulses and disorderly release of LH and testosterone, as measured by the approximate entropy statistic. The mechanisms that underlie such complex adaptations are not known, but appear to involve multiple loci of regulatory failure.

Enrollment: 40 estimated patients

Sex: Male

Ages: 18 to 80 years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion criteria

• Healthy Men Ages 18-80
• All ethnicities eligible
• Men with indeterminate erectile dysfunction eligible with normal serum gonadotropin, total testosterone, prolactin and TSH concentrations and documented integrity of the neurovascular, cardiovascular, hepatorenal systems