Biomaterial Database

Effects of endurance exercise on free testosterone concentration and the binding affinity of sex hormone binding globulin (SHBG). 1998

C L Fahrner, and A C Hackney

Endocrine Section, Applied Physiology Laboratory, University of North Carolina, Chapel Hill 27599-8700, USA.

Our purpose was to examine the changes in free testosterone concentration following moderately prolonged endurance exercise to determine whether such changes were due to alterations in the binding affinity of sex hormone binding globulin (SHBG). Ten trained men completed control (45 min rest) and exercise (45 min @ 70% VO2max) experimental sessions. Blood samples were collected before (pre-) and immediately after (post-) each of the sessions and analyzed for total testosterone, free testosterone, LH, FSH, cortisol, estradiol, SHBG, epinephrine and norepinephrine. The association constant (Ka) of SHBG for testosterone was assessed to evaluate binding affinity. No significant difference was seen between the pre-control and the pre-exercise session values for any of the measures. However, within the exercise session significant (p<0.01) increases in post samples were evident for total testosterone (+32.0%), free-testosterone (+39.6%), cortisol (+38.0%), norepinephrine (+365.2%) and epinephrine (+225.8%). All other hormonal changes and the responses for Ka were non-significant. The results of the correlation analysis indicated that only norepinephrine was significantly (p<0.05) related to the changes observed in free testosterone (r = +0.92). We conclude that the free testosterone increase with moderately, prolonged endurance exercise was not associated with the change in the binding affinity of SHBG. Furthermore, the data suggest that the exercise induced increase in testosterone involves increased production which may be mediated by sympathetic stimulation of the testicles.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009638	Norepinephrine	Precursor of epinephrine that is secreted by the ADRENAL MEDULLA and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers, and of the diffuse projection system in the brain that arises from the LOCUS CERULEUS. It is also found in plants and is used pharmacologically as a sympathomimetic.	Levarterenol,Levonorepinephrine,Noradrenaline,Arterenol,Levonor,Levophed,Levophed Bitartrate,Noradrenaline Bitartrate,Noradrénaline tartrate renaudin,Norepinephrin d-Tartrate (1:1),Norepinephrine Bitartrate,Norepinephrine Hydrochloride,Norepinephrine Hydrochloride, (+)-Isomer,Norepinephrine Hydrochloride, (+,-)-Isomer,Norepinephrine d-Tartrate (1:1),Norepinephrine l-Tartrate (1:1),Norepinephrine l-Tartrate (1:1), (+,-)-Isomer,Norepinephrine l-Tartrate (1:1), Monohydrate,Norepinephrine l-Tartrate (1:1), Monohydrate, (+)-Isomer,Norepinephrine l-Tartrate (1:2),Norepinephrine l-Tartrate, (+)-Isomer,Norepinephrine, (+)-Isomer,Norepinephrine, (+,-)-Isomer
D010807	Physical Endurance	The time span between the beginning of physical activity by an individual and the termination because of exhaustion.	Endurance, Physical,Physical Stamina,Stamina, Physical
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D004837	Epinephrine	The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS.	Adrenaline,4-(1-Hydroxy-2-(methylamino)ethyl)-1,2-benzenediol,Adrenaline Acid Tartrate,Adrenaline Bitartrate,Adrenaline Hydrochloride,Epifrin,Epinephrine Acetate,Epinephrine Bitartrate,Epinephrine Hydrochloride,Epinephrine Hydrogen Tartrate,Epitrate,Lyophrin,Medihaler-Epi,Acetate, Epinephrine
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006854	Hydrocortisone	The main glucocorticoid secreted by the ADRENAL CORTEX. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions.	Cortef,Cortisol,Pregn-4-ene-3,20-dione, 11,17,21-trihydroxy-, (11beta)-,11-Epicortisol,Cortifair,Cortril,Epicortisol,Hydrocortisone, (11 alpha)-Isomer,Hydrocortisone, (9 beta,10 alpha,11 alpha)-Isomer,11 Epicortisol
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D000704	Analysis of Variance	A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.	ANOVA,Analysis, Variance,Variance Analysis,Analyses, Variance,Variance Analyses
D012738	Sex Hormone-Binding Globulin	A glycoprotein migrating as a beta-globulin. Its molecular weight, 52,000 or 95,000-115,000, indicates that it exists as a dimer. The protein binds testosterone, dihydrotestosterone, and estradiol in the plasma. Sex hormone-binding protein has the same amino acid sequence as ANDROGEN-BINDING PROTEIN. They differ by their sites of synthesis and post-translational oligosaccharide modifications.	Sex Steroid-Binding Protein,Testosterone-Estradiol Binding Globulin,Binding Globulin, Testosterone-Estradiol,Globulin, Sex Hormone-Binding,Globulin, Testosterone-Estradiol Binding,Hormone-Binding Globulin, Sex,Sex Hormone Binding Globulin,Sex Steroid Binding Protein,Steroid-Binding Protein, Sex,Testosterone Estradiol Binding Globulin