Nighttime immunoreactive somatostatin content of the median eminence in hypo-and hyperthyroid rats

S. M. Webb, Thomas Champney, R. J. Reiter

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

1. 1. The median eminence content of immunoreactive somatostatin (IRS) was measured by radioimmunoassay in 107 male albino rats, who were either hypothyroid after surgical thyroidectomy (N = 38), hyperthyroid following a subcutaneous implant of 5 mg of l-thyroxine (N = 36), or otherwise untreated (N = 33). 2. 2. Thyroid function was assessed by determining plasma levels of T4 and TSH from trunk blood obtained at the time of decapitation. Subgroups of animals from the 3 groups were killed either before (1800 hr), during (2200, 0200, 0400 hr), or after the dark portion of their 14:10LD photoperiod. 3. 3. Although no changes in median eminence IRS content were found throughout the period of study within any of the 3 groups, hypothyroid animals (297.23 ± 13.47 ng per ME; 620.41 ±58 ngIRS/mg protein) had a significantly lower median eminence IRS concentration than untreated rats (355.86 ± 16.55 ng of IRS per ME, P < 0.01; 906.86 ± 96.38 ng IRS/mg protein, P <0.05) and hyperthyroid animals (384.12 ± 14.67 ng per ME, P < 0.001; 874.1 ± 104.5 ng IRS//mg protein, P < 0.05). 4. 4. It is concluded, that the feedback of thyroid hormones on the hypothalamic-pituitary axis during thyroid hormone excess in vivo, contrary to what occurs in hypothyroidism, is probably independent of hypothalamic somatostatin.

Original languageEnglish
Pages (from-to)575-577
Number of pages3
JournalComparative Biochemistry and Physiology -- Part A: Physiology
Volume80
Issue number4
DOIs
StatePublished - Jan 1 1985
Externally publishedYes

Fingerprint

Median Eminence
Hyperthyroidism
Somatostatin
Rats
Animals
Thyroid Hormones
Decapitation
Proteins
Thyroidectomy
Photoperiod
Hypothyroidism
Thyroxine
Radioimmunoassay
Thyroid Gland
Blood
Feedback
Plasmas

ASJC Scopus subject areas

  • Physiology
  • Molecular Biology
  • Biochemistry

Cite this

Nighttime immunoreactive somatostatin content of the median eminence in hypo-and hyperthyroid rats. / Webb, S. M.; Champney, Thomas; Reiter, R. J.

In: Comparative Biochemistry and Physiology -- Part A: Physiology, Vol. 80, No. 4, 01.01.1985, p. 575-577.

Research output: Contribution to journalArticle

@article{5dd94b435edf4a80a9f4196e2e572f52,
title = "Nighttime immunoreactive somatostatin content of the median eminence in hypo-and hyperthyroid rats",
abstract = "1. 1. The median eminence content of immunoreactive somatostatin (IRS) was measured by radioimmunoassay in 107 male albino rats, who were either hypothyroid after surgical thyroidectomy (N = 38), hyperthyroid following a subcutaneous implant of 5 mg of l-thyroxine (N = 36), or otherwise untreated (N = 33). 2. 2. Thyroid function was assessed by determining plasma levels of T4 and TSH from trunk blood obtained at the time of decapitation. Subgroups of animals from the 3 groups were killed either before (1800 hr), during (2200, 0200, 0400 hr), or after the dark portion of their 14:10LD photoperiod. 3. 3. Although no changes in median eminence IRS content were found throughout the period of study within any of the 3 groups, hypothyroid animals (297.23 ± 13.47 ng per ME; 620.41 ±58 ngIRS/mg protein) had a significantly lower median eminence IRS concentration than untreated rats (355.86 ± 16.55 ng of IRS per ME, P < 0.01; 906.86 ± 96.38 ng IRS/mg protein, P <0.05) and hyperthyroid animals (384.12 ± 14.67 ng per ME, P < 0.001; 874.1 ± 104.5 ng IRS//mg protein, P < 0.05). 4. 4. It is concluded, that the feedback of thyroid hormones on the hypothalamic-pituitary axis during thyroid hormone excess in vivo, contrary to what occurs in hypothyroidism, is probably independent of hypothalamic somatostatin.",
author = "Webb, {S. M.} and Thomas Champney and Reiter, {R. J.}",
year = "1985",
month = "1",
day = "1",
doi = "10.1016/0300-9629(85)90415-3",
language = "English",
volume = "80",
pages = "575--577",
journal = "Comparative Biochemistry & Physiology; A: Comparative Physiology",
issn = "1095-6433",
publisher = "Elsevier Inc.",
number = "4",

}

TY - JOUR

T1 - Nighttime immunoreactive somatostatin content of the median eminence in hypo-and hyperthyroid rats

AU - Webb, S. M.

AU - Champney, Thomas

AU - Reiter, R. J.

PY - 1985/1/1

Y1 - 1985/1/1

N2 - 1. 1. The median eminence content of immunoreactive somatostatin (IRS) was measured by radioimmunoassay in 107 male albino rats, who were either hypothyroid after surgical thyroidectomy (N = 38), hyperthyroid following a subcutaneous implant of 5 mg of l-thyroxine (N = 36), or otherwise untreated (N = 33). 2. 2. Thyroid function was assessed by determining plasma levels of T4 and TSH from trunk blood obtained at the time of decapitation. Subgroups of animals from the 3 groups were killed either before (1800 hr), during (2200, 0200, 0400 hr), or after the dark portion of their 14:10LD photoperiod. 3. 3. Although no changes in median eminence IRS content were found throughout the period of study within any of the 3 groups, hypothyroid animals (297.23 ± 13.47 ng per ME; 620.41 ±58 ngIRS/mg protein) had a significantly lower median eminence IRS concentration than untreated rats (355.86 ± 16.55 ng of IRS per ME, P < 0.01; 906.86 ± 96.38 ng IRS/mg protein, P <0.05) and hyperthyroid animals (384.12 ± 14.67 ng per ME, P < 0.001; 874.1 ± 104.5 ng IRS//mg protein, P < 0.05). 4. 4. It is concluded, that the feedback of thyroid hormones on the hypothalamic-pituitary axis during thyroid hormone excess in vivo, contrary to what occurs in hypothyroidism, is probably independent of hypothalamic somatostatin.

AB - 1. 1. The median eminence content of immunoreactive somatostatin (IRS) was measured by radioimmunoassay in 107 male albino rats, who were either hypothyroid after surgical thyroidectomy (N = 38), hyperthyroid following a subcutaneous implant of 5 mg of l-thyroxine (N = 36), or otherwise untreated (N = 33). 2. 2. Thyroid function was assessed by determining plasma levels of T4 and TSH from trunk blood obtained at the time of decapitation. Subgroups of animals from the 3 groups were killed either before (1800 hr), during (2200, 0200, 0400 hr), or after the dark portion of their 14:10LD photoperiod. 3. 3. Although no changes in median eminence IRS content were found throughout the period of study within any of the 3 groups, hypothyroid animals (297.23 ± 13.47 ng per ME; 620.41 ±58 ngIRS/mg protein) had a significantly lower median eminence IRS concentration than untreated rats (355.86 ± 16.55 ng of IRS per ME, P < 0.01; 906.86 ± 96.38 ng IRS/mg protein, P <0.05) and hyperthyroid animals (384.12 ± 14.67 ng per ME, P < 0.001; 874.1 ± 104.5 ng IRS//mg protein, P < 0.05). 4. 4. It is concluded, that the feedback of thyroid hormones on the hypothalamic-pituitary axis during thyroid hormone excess in vivo, contrary to what occurs in hypothyroidism, is probably independent of hypothalamic somatostatin.

UR - http://www.scopus.com/inward/record.url?scp=0021904949&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0021904949&partnerID=8YFLogxK

U2 - 10.1016/0300-9629(85)90415-3

DO - 10.1016/0300-9629(85)90415-3

M3 - Article

VL - 80

SP - 575

EP - 577

JO - Comparative Biochemistry & Physiology; A: Comparative Physiology

JF - Comparative Biochemistry & Physiology; A: Comparative Physiology

SN - 1095-6433

IS - 4

ER -