Gender differences in growth hormone response to exercise before and after rhGH administration and the effect of rhGH on the hormone profile of fit normal adults

M. G. Giannoulis, Massoud Boroujerdi, J. Powrie, R. Dall, R. Napoli, C. Ehrnborg, J. O. L. Jorgensen, P. H. Soknsen, GH-2000 Study Grp

    Research output: Contribution to journalArticle

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    Abstract

    Objectives Exercise is a potent physiological stimulus of GH secretion. We hypothesized that exogenous recombinant human growth hormone (rhGH) administration through an increase in GH and IGF-I levels would blunt the GH response to exercise. The aim of the study was to examine and compare the impact of rhGH on the exercise-induced GH response in healthy normal men and women.

    Design and Measurements Sixty-nine subjects (36 men, 33 women) were randomized to receive low-dose rhGH (0.1 U/kg/day), high dose rhGH (0.2 U/kg/day), or placebo. Subjects were matched for age (24 +/- 3.1), and body mass index (BMI). rhGH was given as a single subcutaneous (s.c.) injection for the first 28 days. All subjects exercised to exhaustion (maximal oxygen consumption - VO(2)max) before rhGH treatment (Test 1), and on day 28 (Test 2). GH was measured before exercise (time 0), immediately after exercise (time 0') and at 15, 30, 60, 90 and 120 min postexercise. Baseline IGF-I levels were measured before exercise on days 0 and 28.

    Results Baseline IGF-I levels showed no gender differences (42.3 women vs. 38.8 nmol/l men) but basal GH values were higher in women (9.9 vs. 1.8 mU/l, P < 0.001). The areas under the GH response curve, for Test 1 were similar in men and women. Peak GH values were higher in women than men (37.9 vs. 23.5 mU/l, but this did not quite reach statistical significance (P = 0.055). In men, administration of rhGH resulted in a significant increase in IGF-I levels over the basal state in both the LD and HD groups (P < 0.0001). In women, the increase in lGF-I levels reached significance only in the HD group (P < 0.0001). On day 28, GH secretion in response to exercise was calculated from the areas under the GH response curve correcting for an exogenous rhGH component (DeltaAUC). In men, the DeltaAUC, for Test 2 were similar in all three groups. In women, the DeltaAUC was higher in the placebo group, than in the HD group (P < 0.02). Free T4 levels decreased significantly in men, and free T3 increased in both men and women, in HD group after the rhGH administration. TSH levels were suppressed only in women. No changes in sex hormones were found in men or women in any of the treatment groups.

    Conclusions In terms of IGF-I, men are more responsive to rhGH treatment than women. In addition, as men, but not women, were able to overcome the negative feedback control of the elevated IGF-I levels, it seems that exercise may be a more robust stimulus to GH release in men compared to women.

    Original languageEnglish
    Pages (from-to)315-322
    Number of pages7
    JournalClinical Endocrinology
    Volume62
    DOIs
    Publication statusPublished - 2005

    Keywords

    • GH-DEFICIENT ADULTS
    • BINDING-PROTEINS
    • FACTOR AXIS
    • MEN
    • SECRETION
    • WOMEN
    • SEX
    • AGE
    • RELEASE
    • OBESITY

    Cite this

    Gender differences in growth hormone response to exercise before and after rhGH administration and the effect of rhGH on the hormone profile of fit normal adults. / Giannoulis, M. G.; Boroujerdi, Massoud; Powrie, J.; Dall, R.; Napoli, R.; Ehrnborg, C.; Jorgensen, J. O. L.; Soknsen, P. H.; GH-2000 Study Grp.

    In: Clinical Endocrinology, Vol. 62, 2005, p. 315-322.

    Research output: Contribution to journalArticle

    Giannoulis, MG, Boroujerdi, M, Powrie, J, Dall, R, Napoli, R, Ehrnborg, C, Jorgensen, JOL, Soknsen, PH & GH-2000 Study Grp 2005, 'Gender differences in growth hormone response to exercise before and after rhGH administration and the effect of rhGH on the hormone profile of fit normal adults', Clinical Endocrinology, vol. 62, pp. 315-322. https://doi.org/10.1111/j.1365-2265.2005.02216.x
    Giannoulis, M. G. ; Boroujerdi, Massoud ; Powrie, J. ; Dall, R. ; Napoli, R. ; Ehrnborg, C. ; Jorgensen, J. O. L. ; Soknsen, P. H. ; GH-2000 Study Grp. / Gender differences in growth hormone response to exercise before and after rhGH administration and the effect of rhGH on the hormone profile of fit normal adults. In: Clinical Endocrinology. 2005 ; Vol. 62. pp. 315-322.
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    abstract = "Objectives Exercise is a potent physiological stimulus of GH secretion. We hypothesized that exogenous recombinant human growth hormone (rhGH) administration through an increase in GH and IGF-I levels would blunt the GH response to exercise. The aim of the study was to examine and compare the impact of rhGH on the exercise-induced GH response in healthy normal men and women.Design and Measurements Sixty-nine subjects (36 men, 33 women) were randomized to receive low-dose rhGH (0.1 U/kg/day), high dose rhGH (0.2 U/kg/day), or placebo. Subjects were matched for age (24 +/- 3.1), and body mass index (BMI). rhGH was given as a single subcutaneous (s.c.) injection for the first 28 days. All subjects exercised to exhaustion (maximal oxygen consumption - VO(2)max) before rhGH treatment (Test 1), and on day 28 (Test 2). GH was measured before exercise (time 0), immediately after exercise (time 0') and at 15, 30, 60, 90 and 120 min postexercise. Baseline IGF-I levels were measured before exercise on days 0 and 28.Results Baseline IGF-I levels showed no gender differences (42.3 women vs. 38.8 nmol/l men) but basal GH values were higher in women (9.9 vs. 1.8 mU/l, P < 0.001). The areas under the GH response curve, for Test 1 were similar in men and women. Peak GH values were higher in women than men (37.9 vs. 23.5 mU/l, but this did not quite reach statistical significance (P = 0.055). In men, administration of rhGH resulted in a significant increase in IGF-I levels over the basal state in both the LD and HD groups (P < 0.0001). In women, the increase in lGF-I levels reached significance only in the HD group (P < 0.0001). On day 28, GH secretion in response to exercise was calculated from the areas under the GH response curve correcting for an exogenous rhGH component (DeltaAUC). In men, the DeltaAUC, for Test 2 were similar in all three groups. In women, the DeltaAUC was higher in the placebo group, than in the HD group (P < 0.02). Free T4 levels decreased significantly in men, and free T3 increased in both men and women, in HD group after the rhGH administration. TSH levels were suppressed only in women. No changes in sex hormones were found in men or women in any of the treatment groups.Conclusions In terms of IGF-I, men are more responsive to rhGH treatment than women. In addition, as men, but not women, were able to overcome the negative feedback control of the elevated IGF-I levels, it seems that exercise may be a more robust stimulus to GH release in men compared to women.",
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    author = "Giannoulis, {M. G.} and Massoud Boroujerdi and J. Powrie and R. Dall and R. Napoli and C. Ehrnborg and Jorgensen, {J. O. L.} and Soknsen, {P. H.} and {GH-2000 Study Grp}",
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    TY - JOUR

    T1 - Gender differences in growth hormone response to exercise before and after rhGH administration and the effect of rhGH on the hormone profile of fit normal adults

    AU - Giannoulis, M. G.

    AU - Boroujerdi, Massoud

    AU - Powrie, J.

    AU - Dall, R.

    AU - Napoli, R.

    AU - Ehrnborg, C.

    AU - Jorgensen, J. O. L.

    AU - Soknsen, P. H.

    AU - GH-2000 Study Grp

    PY - 2005

    Y1 - 2005

    N2 - Objectives Exercise is a potent physiological stimulus of GH secretion. We hypothesized that exogenous recombinant human growth hormone (rhGH) administration through an increase in GH and IGF-I levels would blunt the GH response to exercise. The aim of the study was to examine and compare the impact of rhGH on the exercise-induced GH response in healthy normal men and women.Design and Measurements Sixty-nine subjects (36 men, 33 women) were randomized to receive low-dose rhGH (0.1 U/kg/day), high dose rhGH (0.2 U/kg/day), or placebo. Subjects were matched for age (24 +/- 3.1), and body mass index (BMI). rhGH was given as a single subcutaneous (s.c.) injection for the first 28 days. All subjects exercised to exhaustion (maximal oxygen consumption - VO(2)max) before rhGH treatment (Test 1), and on day 28 (Test 2). GH was measured before exercise (time 0), immediately after exercise (time 0') and at 15, 30, 60, 90 and 120 min postexercise. Baseline IGF-I levels were measured before exercise on days 0 and 28.Results Baseline IGF-I levels showed no gender differences (42.3 women vs. 38.8 nmol/l men) but basal GH values were higher in women (9.9 vs. 1.8 mU/l, P < 0.001). The areas under the GH response curve, for Test 1 were similar in men and women. Peak GH values were higher in women than men (37.9 vs. 23.5 mU/l, but this did not quite reach statistical significance (P = 0.055). In men, administration of rhGH resulted in a significant increase in IGF-I levels over the basal state in both the LD and HD groups (P < 0.0001). In women, the increase in lGF-I levels reached significance only in the HD group (P < 0.0001). On day 28, GH secretion in response to exercise was calculated from the areas under the GH response curve correcting for an exogenous rhGH component (DeltaAUC). In men, the DeltaAUC, for Test 2 were similar in all three groups. In women, the DeltaAUC was higher in the placebo group, than in the HD group (P < 0.02). Free T4 levels decreased significantly in men, and free T3 increased in both men and women, in HD group after the rhGH administration. TSH levels were suppressed only in women. No changes in sex hormones were found in men or women in any of the treatment groups.Conclusions In terms of IGF-I, men are more responsive to rhGH treatment than women. In addition, as men, but not women, were able to overcome the negative feedback control of the elevated IGF-I levels, it seems that exercise may be a more robust stimulus to GH release in men compared to women.

    AB - Objectives Exercise is a potent physiological stimulus of GH secretion. We hypothesized that exogenous recombinant human growth hormone (rhGH) administration through an increase in GH and IGF-I levels would blunt the GH response to exercise. The aim of the study was to examine and compare the impact of rhGH on the exercise-induced GH response in healthy normal men and women.Design and Measurements Sixty-nine subjects (36 men, 33 women) were randomized to receive low-dose rhGH (0.1 U/kg/day), high dose rhGH (0.2 U/kg/day), or placebo. Subjects were matched for age (24 +/- 3.1), and body mass index (BMI). rhGH was given as a single subcutaneous (s.c.) injection for the first 28 days. All subjects exercised to exhaustion (maximal oxygen consumption - VO(2)max) before rhGH treatment (Test 1), and on day 28 (Test 2). GH was measured before exercise (time 0), immediately after exercise (time 0') and at 15, 30, 60, 90 and 120 min postexercise. Baseline IGF-I levels were measured before exercise on days 0 and 28.Results Baseline IGF-I levels showed no gender differences (42.3 women vs. 38.8 nmol/l men) but basal GH values were higher in women (9.9 vs. 1.8 mU/l, P < 0.001). The areas under the GH response curve, for Test 1 were similar in men and women. Peak GH values were higher in women than men (37.9 vs. 23.5 mU/l, but this did not quite reach statistical significance (P = 0.055). In men, administration of rhGH resulted in a significant increase in IGF-I levels over the basal state in both the LD and HD groups (P < 0.0001). In women, the increase in lGF-I levels reached significance only in the HD group (P < 0.0001). On day 28, GH secretion in response to exercise was calculated from the areas under the GH response curve correcting for an exogenous rhGH component (DeltaAUC). In men, the DeltaAUC, for Test 2 were similar in all three groups. In women, the DeltaAUC was higher in the placebo group, than in the HD group (P < 0.02). Free T4 levels decreased significantly in men, and free T3 increased in both men and women, in HD group after the rhGH administration. TSH levels were suppressed only in women. No changes in sex hormones were found in men or women in any of the treatment groups.Conclusions In terms of IGF-I, men are more responsive to rhGH treatment than women. In addition, as men, but not women, were able to overcome the negative feedback control of the elevated IGF-I levels, it seems that exercise may be a more robust stimulus to GH release in men compared to women.

    KW - GH-DEFICIENT ADULTS

    KW - BINDING-PROTEINS

    KW - FACTOR AXIS

    KW - MEN

    KW - SECRETION

    KW - WOMEN

    KW - SEX

    KW - AGE

    KW - RELEASE

    KW - OBESITY

    U2 - 10.1111/j.1365-2265.2005.02216.x

    DO - 10.1111/j.1365-2265.2005.02216.x

    M3 - Article

    VL - 62

    SP - 315

    EP - 322

    JO - Clinical Endocrinology

    JF - Clinical Endocrinology

    SN - 0300-0664

    ER -