TY - JOUR
T1 - Serum levels of sex hormone-binding globulin (SHBG) are not associated with lower levels of non-SHBG-bound testosterone in male newborns and healthy adult men
AU - De Ronde, Willem
AU - Van Der Schouw, Yvonne T.
AU - Pierik, Frank H.
AU - Pols, Huibert A.P.
AU - Muller, Majon
AU - Grobbee, Diederick E.
AU - Gooren, Louis J.G.
AU - Weber, Rob F.A.
AU - De Jong, Frank H.
PY - 2005/4/1
Y1 - 2005/4/1
N2 - 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 (β) 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 (β = 0.02 ± 0.004, r = 0.44, P < 0.001) but not with non-SHBG-T (β = -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 (β = 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 β = 0.02 (P = 0.32), β = 0.04 (P = 0.03), β = 0.04 (P = 0.02) and β = 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.
AB - 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 (β) 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 (β = 0.02 ± 0.004, r = 0.44, P < 0.001) but not with non-SHBG-T (β = -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 (β = 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 β = 0.02 (P = 0.32), β = 0.04 (P = 0.03), β = 0.04 (P = 0.02) and β = 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.
UR - http://www.scopus.com/inward/record.url?scp=17044397684&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2265.2005.02252.x
DO - 10.1111/j.1365-2265.2005.02252.x
M3 - Article
C2 - 15807883
AN - SCOPUS:17044397684
SN - 0300-0664
VL - 62
SP - 498
EP - 503
JO - Clinical Endocrinology
JF - Clinical Endocrinology
IS - 4
ER -