Usage Information

Decreased hypothalamic growth hormone-releasing hormone content and pituitary responsiveness in hypothyroidism.
H Katakami, … , T R Downs, L A Frohman
H Katakami, … , T R Downs, L A Frohman
Published May 1, 1986
Citation Information: J Clin Invest. 1986;77(5):1704-1711. https://doi.org/10.1172/JCI112490.
View: Text | PDF
Research Article

Decreased hypothalamic growth hormone-releasing hormone content and pituitary responsiveness in hypothyroidism.

Abstract

The effects of thyroidectomy (Tx) and thyroxine replacement (T4Rx) on pituitary growth hormone (GH) secretion and hypothalamic GH-releasing hormone (GRH) concentration were compared to define the mechanism of hypothyroid-associated GH deficiency. Thyroidectomized rats exhibited a complete loss of pulsatile GH secretion with extensive reduction in GRH responsiveness and pituitary GH content. Cultured pituitary cells from Tx rats exhibited reduced GRH sensitivity, maximal GH responsiveness, and intracellular cyclic AMP accumulation to GRH, while somatostatin (SRIF) suppressive effects on GH secretion were increased. Hypothalamic GRH content was also markedly reduced. T4Rx completely restored hypothalamic GRH content and spontaneous GH secretion despite only partial recovery of pituitary GH content, GRH and SRIF sensitivity, and intracellular cyclic AMP response to GRH. The results indicate multiple effects of hypothyroidism on GH secretion and suggest that a critical role of T4 in maintaining normal GH secretion, in addition to restoring GH synthesis, is related to its effect on hypothalamic GRH.

Authors

H Katakami, T R Downs, L A Frohman

×

Usage data is cumulative from April 2024 through April 2025.

Usage JCI PMC
Text version 159 2
PDF 45 17
Figure 0 1
Scanned page 269 4
Citation downloads 43 0
Totals 516 24
Total Views 540
(Click and drag on plot area to zoom in. Click legend items above to toggle)

Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.

Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.

Advertisement