OBJECTIVE: It is generally accepted that SHBG decreases the bioavailability and activity of testosterone (T). In in vitro experiments increased levels of SHBG will be associated with decreased levels of non-SHBG bound testosterone (non-SHBG-T). However, in vivo SHBG can alter both production and clearance rates and thus plasma levels of T. DESIGN AND PATIENTS: In order to study the effect of SHBG on the levels of non-SHBG-T in vivo in the presence of an active hypothalamo-pituitary-gonadal (HPG) axis we conducted a cross sectional study in 400 healthy adult men with an age range of 40-80 years and in 106 newborn boys. MEASUREMENTS: In both groups, regression coefficients (beta) and partial correlation coefficients (r) were calculated for the relationship between SHBG and T or non-SHBG-T. Adult men were divided into age groups per decade (40-50 years, 51-60 years, 61-70 years and 71-80 years) to study possible differences in the impact of SHBG on the level of non-SHBG-T throughout ageing. RESULTS: Higher levels of SHBG were associated with higher levels of total testosterone in neonates (beta = 0.02 +/- 0.004, r = 0.44, P < 0.001) but not with non-SHBG-T (beta = -0.001 +/- 0.001, r = 0.05, P = 0.52). In adult men there was a significant age related increase in levels of SHBG and an age-related decrease of both total and non-SHBG-T. Higher SHBG was strongly associated with higher total testosterone in all age groups (beta = 0.26, 0.26, 0.26 and 0.23 for 40-50 years, 51-60 years, 61-70 years and 71-80 years, respectively, P < 0.001 for all age groups). Higher SHBG was not or only slightly associated with higher non-SHBG-T beta = 0.02 (P = 0.32), beta = 0.04 (P = 0.03), beta = 0.04 (P = 0.02) and beta = 0.02 (P = 0.16) for 40-50 years, 51-60 years, 61-70 years and 71-80 years, respectively. CONCLUSIONS: In contrast to general belief, SHBG levels barely influence levels of non-SHBG-bound testosterone both in male newborns and healthy adult men: the influence, if any, is positive. Consequently the age related increase of SHBG does not account for the age related decline in non-SHBG-T in healthy adult men.
OBJECTIVE: It is generally accepted that SHBG decreases the bioavailability and activity of testosterone (T). In in vitro experiments increased levels of SHBG will be associated with decreased levels of non-SHBG bound testosterone (non-SHBG-T). However, in vivo SHBG can alter both production and clearance rates and thus plasma levels of T. DESIGN AND PATIENTS: In order to study the effect of SHBG on the levels of non-SHBG-T in vivo in the presence of an active hypothalamo-pituitary-gonadal (HPG) axis we conducted a cross sectional study in 400 healthy adult men with an age range of 40-80 years and in 106 newborn boys. MEASUREMENTS: In both groups, regression coefficients (beta) and partial correlation coefficients (r) were calculated for the relationship between SHBG and T or non-SHBG-T. Adult men were divided into age groups per decade (40-50 years, 51-60 years, 61-70 years and 71-80 years) to study possible differences in the impact of SHBG on the level of non-SHBG-T throughout ageing. RESULTS: Higher levels of SHBG were associated with higher levels of total testosterone in neonates (beta = 0.02 +/- 0.004, r = 0.44, P < 0.001) but not with non-SHBG-T (beta = -0.001 +/- 0.001, r = 0.05, P = 0.52). In adult men there was a significant age related increase in levels of SHBG and an age-related decrease of both total and non-SHBG-T. Higher SHBG was strongly associated with higher total testosterone in all age groups (beta = 0.26, 0.26, 0.26 and 0.23 for 40-50 years, 51-60 years, 61-70 years and 71-80 years, respectively, P < 0.001 for all age groups). Higher SHBG was not or only slightly associated with higher non-SHBG-T beta = 0.02 (P = 0.32), beta = 0.04 (P = 0.03), beta = 0.04 (P = 0.02) and beta = 0.02 (P = 0.16) for 40-50 years, 51-60 years, 61-70 years and 71-80 years, respectively. CONCLUSIONS: In contrast to general belief, SHBG levels barely influence levels of non-SHBG-bound testosterone both in male newborns and healthy adult men: the influence, if any, is positive. Consequently the age related increase of SHBG does not account for the age related decline in non-SHBG-T in healthy adult men.
Authors: Lawrence D Hayes; Nicholas Sculthorpe; Peter Herbert; Julien S Baker; David A Hullin; Liam P Kilduff; Dewi Reed; Roberto Spagna; Fergal M Grace Journal: Endocrine Date: 2014-12-27 Impact factor: 3.633
Authors: Eleanor L Watts; Paul N Appleby; Demetrius Albanes; Amanda Black; June M Chan; Chu Chen; Piera M Cirillo; Barbara A Cohn; Michael B Cook; Jenny L Donovan; Luigi Ferrucci; Cedric F Garland; Graham G Giles; Phyllis J Goodman; Laurel A Habel; Christopher A Haiman; Jeff M P Holly; Robert N Hoover; Rudolf Kaaks; Paul Knekt; Laurence N Kolonel; Tatsuhiko Kubo; Loïc Le Marchand; Tapio Luostarinen; Robert J MacInnis; Hanna O Mäenpää; Satu Männistö; E Jeffrey Metter; Roger L Milne; Abraham M Y Nomura; Steven E Oliver; J Kellogg Parsons; Petra H Peeters; Elizabeth A Platz; Elio Riboli; Fulvio Ricceri; Sabina Rinaldi; Harri Rissanen; Norie Sawada; Catherine A Schaefer; Jeannette M Schenk; Frank Z Stanczyk; Meir Stampfer; Pär Stattin; Ulf-Håkan Stenman; Anne Tjønneland; Antonia Trichopoulou; Ian M Thompson; Shoichiro Tsugane; Lars Vatten; Alice S Whittemore; Regina G Ziegler; Naomi E Allen; Timothy J Key; Ruth C Travis Journal: PLoS One Date: 2017-12-27 Impact factor: 3.752
Authors: Jaap J M Teunissen; Eric P Krenning; Frank H de Jong; Yolanda B de Rijke; Richard A Feelders; Maarten O van Aken; Wouter W de Herder; Dik J Kwekkeboom Journal: Eur J Nucl Med Mol Imaging Date: 2009-05-27 Impact factor: 9.236
Authors: Louise Scheutz Henriksen; Jørgen Holm Petersen; Niels E Skakkebæk; Niels Jørgensen; Helena E Virtanen; Lærke Priskorn; Anders Juul; Jorma Toppari; Katharina M Main Journal: J Clin Endocrinol Metab Date: 2022-06-16 Impact factor: 6.134