title: Effects of testosterone administration on nocturnal cortisol secretion in healthy older men.
abstract: In animal studies, testosterone decreases, whereas estrogen increases, cortisol production. In one clinical study, short-term testosterone replacement attenuated corticotrophin-releasing hormone-stimulated cortisol secretion during leuprolide-induced hypogonadism in young men. The effects of longer term testosterone treatment on spontaneous cortisol secretion in younger or older men are unknown. In a randomized, double-masked placebo-controlled study, we assessed the effects of testosterone supplementation (100 mg intramuscular every 2 week) for 26 weeks on nocturnal cortisol secretory dynamics in healthy older men. Testosterone administration increased early morning serum concentrations of free testosterone by 34%, decreased sex hormone-binding globulin by 20%, and did not alter early morning concentrations of cortisol-binding globulin or cortisol compared with placebo treatment. Testosterone did not significantly alter nocturnal mean and integrated cortisol concentrations, cortisol burst frequency, mass/burst, basal secretion, pulsatile cortisol production rate, pattern regularity, or approximate entropy. We conclude that low-dose testosterone supplementation for 26 weeks does not affect spontaneous nocturnal cortisol secretion in healthy older men.
authors.affiliation: Diabetes Unit, Laboratory of Clinical Investigation, National Center for Complementary and Alternative Medicine, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Ranganath
authors.initials: R
authors.lastname: Muniyappa
authors.forename: Johannes D
authors.initials: JD
authors.lastname: Veldhuis
authors.forename: S Mitchell
authors.initials: SM
authors.lastname: Harman
authors.forename: John D
authors.initials: JD
authors.lastname: Sorkin
authors.forename: Marc R
authors.initials: MR
authors.lastname: Blackman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D002940:Circadian Rhythm / Q000502:physiology*; D004311:Double-Blind Method; D004967:Estrogens / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D005260:Female; D019382:Human Growth Hormone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D010919:Placebos; D011372:Progestins / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D011863:Radioimmunoassay; D012680:Sensitivity and Specificity; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*
chemical_list: D004967:Estrogens; D010919:Placebos; D011372:Progestins; D012738:Sex Hormone-Binding Globulin; D019382:Human Growth Hormone; D013739:Testosterone; D006854:Hydrocortisone