Pituitary reserve after repeated administrations of releasing hormones in young and in elderly men: Reproducibility on different days

A. E. Pontiroli, S. Ruga, P. Maffi, L. Scaglia, M. G. Perfetti, G. Pozza

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Combined testing of the pituitary gland by administration of GHRH, CRH, GnRH and TRH has been proposed for clinical studies, although some reports indicate that individual endocrine responses can be different when releasing hormones are used alone or in combination. Aims of this study were to evaluate: 1) the reproducibility of the combined test on different days; 2) the endocrine responses to the combined test applied twice at 3h and at 5h interval; 3) differences of endocrine responses in young and in elderly men. Six healthy young men (aged 25 to 35 yr) and 6 healthy elderly men (aged 65 to 75 yr) were evaluated: elderly men had lower testosterone, free T3, and somatomedin-c levels than young men, while 17ß-estradiol and inhibin were not significantly different, all values being within normal laboratory limits. The 12 men were tested on day 1 with iv GHRH (50 μg) CRH (50 μg), GnRH (100 μg) and TRH (200 μ g) at 08:00h and again at 11:00h; on day 8, the same men were tested at 08:00h and again at 13:00h. At 08:00h, the endocrine responses were similar on day 1 and on day 8. The second GH (young and elderly men) and PRL (only young men) response was blunted on day 1, when the interval between two consecutive stimuli was 3h, but not on day 8, when the interval was 5h. Elderly men differed from young men only for GH and for PRL release on day 1 at 08:00h. Because of a similar behaviour, young and elderly men were then considered together; the second LH and TSH response was blunted on day 1, and the second LH and FSH response was blunted on day 8. The second Cortisol response was usually higher than the first response, the difference being statistically significant on day 1, not on day 8. These data indicate that: 1) the combined administration of the four releasing hormones is reproducible on different days. 2) when two consecutive stimuli are applied, the time required by each endocrine response to return to normal is different; 3) elderly men had a reduced GH and PRL release in comparison to young men; 4) the fact that elderly men had a FSH, LH, and TSH release similar to young men in spite of lower free T3 and testosterone levels speaks in favour of a reduced, or nonproportional, hypothalamic/pituitary endocrine function in healthy elderly men.

Original languageEnglish
Pages (from-to)559-566
Number of pages8
JournalJournal of Endocrinological Investigation
Volume15
Issue number8
DOIs
Publication statusPublished - 1992

Fingerprint

Hormones
Gonadotropin-Releasing Hormone
Testosterone
Inhibins
Somatomedins
Pituitary Gland
Hydrocortisone
Estradiol

Keywords

  • 17ß-estradiol
  • Aging
  • Cortisol
  • FSH
  • inhibin
  • LH
  • physiology
  • pituitary gland
  • prolactin
  • somatomedins
  • somatotropin
  • testosterone
  • thyrotropin

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

Pituitary reserve after repeated administrations of releasing hormones in young and in elderly men : Reproducibility on different days. / Pontiroli, A. E.; Ruga, S.; Maffi, P.; Scaglia, L.; Perfetti, M. G.; Pozza, G.

In: Journal of Endocrinological Investigation, Vol. 15, No. 8, 1992, p. 559-566.

Research output: Contribution to journalArticle

@article{9cbaa3179fb54781bb68efd682a818cf,
title = "Pituitary reserve after repeated administrations of releasing hormones in young and in elderly men: Reproducibility on different days",
abstract = "Combined testing of the pituitary gland by administration of GHRH, CRH, GnRH and TRH has been proposed for clinical studies, although some reports indicate that individual endocrine responses can be different when releasing hormones are used alone or in combination. Aims of this study were to evaluate: 1) the reproducibility of the combined test on different days; 2) the endocrine responses to the combined test applied twice at 3h and at 5h interval; 3) differences of endocrine responses in young and in elderly men. Six healthy young men (aged 25 to 35 yr) and 6 healthy elderly men (aged 65 to 75 yr) were evaluated: elderly men had lower testosterone, free T3, and somatomedin-c levels than young men, while 17{\ss}-estradiol and inhibin were not significantly different, all values being within normal laboratory limits. The 12 men were tested on day 1 with iv GHRH (50 μg) CRH (50 μg), GnRH (100 μg) and TRH (200 μ g) at 08:00h and again at 11:00h; on day 8, the same men were tested at 08:00h and again at 13:00h. At 08:00h, the endocrine responses were similar on day 1 and on day 8. The second GH (young and elderly men) and PRL (only young men) response was blunted on day 1, when the interval between two consecutive stimuli was 3h, but not on day 8, when the interval was 5h. Elderly men differed from young men only for GH and for PRL release on day 1 at 08:00h. Because of a similar behaviour, young and elderly men were then considered together; the second LH and TSH response was blunted on day 1, and the second LH and FSH response was blunted on day 8. The second Cortisol response was usually higher than the first response, the difference being statistically significant on day 1, not on day 8. These data indicate that: 1) the combined administration of the four releasing hormones is reproducible on different days. 2) when two consecutive stimuli are applied, the time required by each endocrine response to return to normal is different; 3) elderly men had a reduced GH and PRL release in comparison to young men; 4) the fact that elderly men had a FSH, LH, and TSH release similar to young men in spite of lower free T3 and testosterone levels speaks in favour of a reduced, or nonproportional, hypothalamic/pituitary endocrine function in healthy elderly men.",
keywords = "17{\ss}-estradiol, Aging, Cortisol, FSH, inhibin, LH, physiology, pituitary gland, prolactin, somatomedins, somatotropin, testosterone, thyrotropin",
author = "Pontiroli, {A. E.} and S. Ruga and P. Maffi and L. Scaglia and Perfetti, {M. G.} and G. Pozza",
year = "1992",
doi = "10.1007/BF03344925",
language = "English",
volume = "15",
pages = "559--566",
journal = "Journal of Endocrinological Investigation",
issn = "0391-4097",
publisher = "Springer International Publishing",
number = "8",

}

TY - JOUR

T1 - Pituitary reserve after repeated administrations of releasing hormones in young and in elderly men

T2 - Reproducibility on different days

AU - Pontiroli, A. E.

AU - Ruga, S.

AU - Maffi, P.

AU - Scaglia, L.

AU - Perfetti, M. G.

AU - Pozza, G.

PY - 1992

Y1 - 1992

N2 - Combined testing of the pituitary gland by administration of GHRH, CRH, GnRH and TRH has been proposed for clinical studies, although some reports indicate that individual endocrine responses can be different when releasing hormones are used alone or in combination. Aims of this study were to evaluate: 1) the reproducibility of the combined test on different days; 2) the endocrine responses to the combined test applied twice at 3h and at 5h interval; 3) differences of endocrine responses in young and in elderly men. Six healthy young men (aged 25 to 35 yr) and 6 healthy elderly men (aged 65 to 75 yr) were evaluated: elderly men had lower testosterone, free T3, and somatomedin-c levels than young men, while 17ß-estradiol and inhibin were not significantly different, all values being within normal laboratory limits. The 12 men were tested on day 1 with iv GHRH (50 μg) CRH (50 μg), GnRH (100 μg) and TRH (200 μ g) at 08:00h and again at 11:00h; on day 8, the same men were tested at 08:00h and again at 13:00h. At 08:00h, the endocrine responses were similar on day 1 and on day 8. The second GH (young and elderly men) and PRL (only young men) response was blunted on day 1, when the interval between two consecutive stimuli was 3h, but not on day 8, when the interval was 5h. Elderly men differed from young men only for GH and for PRL release on day 1 at 08:00h. Because of a similar behaviour, young and elderly men were then considered together; the second LH and TSH response was blunted on day 1, and the second LH and FSH response was blunted on day 8. The second Cortisol response was usually higher than the first response, the difference being statistically significant on day 1, not on day 8. These data indicate that: 1) the combined administration of the four releasing hormones is reproducible on different days. 2) when two consecutive stimuli are applied, the time required by each endocrine response to return to normal is different; 3) elderly men had a reduced GH and PRL release in comparison to young men; 4) the fact that elderly men had a FSH, LH, and TSH release similar to young men in spite of lower free T3 and testosterone levels speaks in favour of a reduced, or nonproportional, hypothalamic/pituitary endocrine function in healthy elderly men.

AB - Combined testing of the pituitary gland by administration of GHRH, CRH, GnRH and TRH has been proposed for clinical studies, although some reports indicate that individual endocrine responses can be different when releasing hormones are used alone or in combination. Aims of this study were to evaluate: 1) the reproducibility of the combined test on different days; 2) the endocrine responses to the combined test applied twice at 3h and at 5h interval; 3) differences of endocrine responses in young and in elderly men. Six healthy young men (aged 25 to 35 yr) and 6 healthy elderly men (aged 65 to 75 yr) were evaluated: elderly men had lower testosterone, free T3, and somatomedin-c levels than young men, while 17ß-estradiol and inhibin were not significantly different, all values being within normal laboratory limits. The 12 men were tested on day 1 with iv GHRH (50 μg) CRH (50 μg), GnRH (100 μg) and TRH (200 μ g) at 08:00h and again at 11:00h; on day 8, the same men were tested at 08:00h and again at 13:00h. At 08:00h, the endocrine responses were similar on day 1 and on day 8. The second GH (young and elderly men) and PRL (only young men) response was blunted on day 1, when the interval between two consecutive stimuli was 3h, but not on day 8, when the interval was 5h. Elderly men differed from young men only for GH and for PRL release on day 1 at 08:00h. Because of a similar behaviour, young and elderly men were then considered together; the second LH and TSH response was blunted on day 1, and the second LH and FSH response was blunted on day 8. The second Cortisol response was usually higher than the first response, the difference being statistically significant on day 1, not on day 8. These data indicate that: 1) the combined administration of the four releasing hormones is reproducible on different days. 2) when two consecutive stimuli are applied, the time required by each endocrine response to return to normal is different; 3) elderly men had a reduced GH and PRL release in comparison to young men; 4) the fact that elderly men had a FSH, LH, and TSH release similar to young men in spite of lower free T3 and testosterone levels speaks in favour of a reduced, or nonproportional, hypothalamic/pituitary endocrine function in healthy elderly men.

KW - 17ß-estradiol

KW - Aging

KW - Cortisol

KW - FSH

KW - inhibin

KW - LH

KW - physiology

KW - pituitary gland

KW - prolactin

KW - somatomedins

KW - somatotropin

KW - testosterone

KW - thyrotropin

UR - http://www.scopus.com/inward/record.url?scp=0026439853&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0026439853&partnerID=8YFLogxK

U2 - 10.1007/BF03344925

DO - 10.1007/BF03344925

M3 - Article

C2 - 1430839

AN - SCOPUS:0026439853

VL - 15

SP - 559

EP - 566

JO - Journal of Endocrinological Investigation

JF - Journal of Endocrinological Investigation

SN - 0391-4097

IS - 8

ER -