Hormonal regulation of rat hypothalamic neuropeptide mRNAs: Effect of hypophysectomy and hormone replacement on growth-hormone-releasing factor, somatostatin and the insulin-like growth factors

Teresa L. Wood, Michael Berelowitz, Marie C. Gelato, Charles Roberts, Derek LeRoith, William J. Millard, Jeffrey F. McKelvy

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Hormonal feedback regulation of hypothalamic peptides putatively involved in growth hormone (GH) regulation has been studied by measurement of steady-state mRNA levels in male hypophysectomized rats with or without thyroid hormone. corticosterone, testosterone or GH replacement. Hypothalamic GH-releasing factor (GRF) mRNA levels increased progressively following hypophysectomy to 420% of sham levels after 15 days while hypothalamic insulin-like growth factor I (IGF-I) and insulin-like growth factor II (IGF-II) mRNA levels decreased to less than 40% of sham levels. Whole hypothalamic somatostatin mRNA levels were not significantly different from sham. One week of continuous GH infusion restored hypothalamic IGF-I mRNA to levels (95%) indistinguishable from those in sham-operated controls but had no effect on either IGF-II or GRF mRNA. Thyroid hormone, corticosterone and testosterone treatment without GH had no effect on the hypophysectomy-induced reduction of either IGF-I or IGF-II mRNA levels but reversed the elevation of GRF mRNA. We conclude that hypothalamic IGF-I may be involved in GH feedback regulation and thus may function as a hypothalamic modulator of GH. In contrast, IGF-II may be regulated by one of the pituitary trophic hormones but not by GH or the target hormones tested. Finally, hypothalamic GRF mRNA regulation appears to be complex and may include target hormone feedback.

Original languageEnglish (US)
Pages (from-to)298-305
Number of pages8
JournalNeuroendocrinology
Volume53
Issue number3
DOIs
StatePublished - 1991
Externally publishedYes

Fingerprint

Growth Hormone-Releasing Hormone
Hypophysectomy
Somatomedins
Somatostatin
Neuropeptides
Hormones
Growth Hormone
Messenger RNA
Insulin-Like Growth Factor II
Insulin-Like Growth Factor I
Corticosterone
Thyroid Hormones
Testosterone
Hypothalamic Hormones
Pituitary Hormone-Releasing Hormones
Pituitary Hormones
Peptides

Keywords

  • Growth hormone
  • Growth-hormone-releasing factor
  • Hypothalamus
  • Insulin-like growth factor I
  • Insulin-like growth factor II
  • MRNA regulation
  • Rat
  • Somatostatin

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism
  • Cellular and Molecular Neuroscience
  • Endocrine and Autonomic Systems
  • Neuroscience(all)

Cite this

Hormonal regulation of rat hypothalamic neuropeptide mRNAs : Effect of hypophysectomy and hormone replacement on growth-hormone-releasing factor, somatostatin and the insulin-like growth factors. / Wood, Teresa L.; Berelowitz, Michael; Gelato, Marie C.; Roberts, Charles; LeRoith, Derek; Millard, William J.; McKelvy, Jeffrey F.

In: Neuroendocrinology, Vol. 53, No. 3, 1991, p. 298-305.

Research output: Contribution to journalArticle

Wood, Teresa L. ; Berelowitz, Michael ; Gelato, Marie C. ; Roberts, Charles ; LeRoith, Derek ; Millard, William J. ; McKelvy, Jeffrey F. / Hormonal regulation of rat hypothalamic neuropeptide mRNAs : Effect of hypophysectomy and hormone replacement on growth-hormone-releasing factor, somatostatin and the insulin-like growth factors. In: Neuroendocrinology. 1991 ; Vol. 53, No. 3. pp. 298-305.
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