title: Effects of resistance training on testosterone metabolism in younger and older men.
abstract: This study investigated the effects of resistance training (RT) on the metabolism of testosterone (T) in younger (n=5, 28±3yrs.) and older (n=8, 70±2yrs.) men. Experimental heavy resistance exercises (5×10RM leg presses) were performed before and after a 12-month of RT. No age differences were found in the production or metabolic clearance rate of T (determined by stable isotope dilution method), skeletal muscle androgen receptor content or serum LH concentrations due to acute or chronic RT. The T production capacity response to gonadotropin stimulation and the concentrations of the urinary T metabolites (androsterone and etiocholanolone) were lower in the older compared to younger men (p<0.05-0.01). This study further showed that RT may have acute effect on T production and clearance rates, while the exercise-induced increases in serum T appeared to be induced by decreased metabolic clearance rate of T. Attenuated T production capacity and urinary excretion of T metabolites in older men may reflect the known reduction in testicular steroidogenesis upon aging. No changes were observed in T metabolism due to RT indicating a homeostatic stability for this hormone in men of different ages.
authors.affiliation: Department of Biology of Physical Activity, University of Jyväskylä, Finland. Electronic address: juha.ahtiainen@jyu.fi.
authors.forename: Juha P
authors.initials: JP
authors.lastname: Ahtiainen
authors.affiliation: Department of Cardiology, Central Hospital, Jyväskylä, Finland.
authors.forename: Kai
authors.initials: K
authors.lastname: Nyman
authors.affiliation: Department of Physiology, University of Turku, Finland; Department of Surgery and Cancer, Imperial College London, Hammersmith Campus, London, UK.
authors.forename: Ilpo
authors.initials: I
authors.lastname: Huhtaniemi
authors.affiliation: Department of Clinical Physiology, Central Hospital, Jyväskylä, Finland.
authors.forename: Tapani
authors.initials: T
authors.lastname: Parviainen
authors.affiliation: Department of Gynecology, Central Hospital, Jyväskylä, Finland.
authors.forename: Mika
authors.initials: M
authors.lastname: Helste
authors.affiliation: Department of Urology, University of Helsinki, Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Rannikko
authors.affiliation: The Department of Human Sciences, The Ohio State University, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Kraemer
authors.affiliation: Department of Biology of Physical Activity, University of Jyväskylä, Finland.
authors.forename: Keijo
authors.initials: K
authors.lastname: Häkkinen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D000738:Androsterone / Q000652:urine; D005043:Etiocholanolone / Q000652:urine; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007553:Isotope Labeling / Q000379:methods; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D063868:Patient Outcome Assessment; D011944:Receptors, Androgen / Q000097:blood*; D065667:Renal Elimination / Q000502:physiology; D055070:Resistance Training / Q000379:methods*; D013739:Testosterone / Q000097:blood / Q000378:metabolism
chemical_list: D011944:Receptors, Androgen; D013739:Testosterone; D005043:Etiocholanolone; D000738:Androsterone
keywords: Androgen receptor; Androsterone; Etiocholanolone; GnRH; Luteinizing hormone