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Experimental Approach to Examine Leptin Signaling in the Carotid Bodies and its Effects on Control of Breathing
Published on: October 25, 2019
Interaction between leptin and growth hormone (GH)/IGF-I axis.
O Isozaki1, T Tsushima, M Miyakawa
1Department of Medicine, Institute of Clinical Endocrinology, Tokyo Women's Medical College, Japan.
Endocrine Journal
|June 11, 2002
Summary
Growth hormone (GH) reduces body fat and leptin expression in visceral fat. Leptin may not directly affect GH release, but GH influences adipose tissue, indicating a complex interaction.
Area of Science:
- Endocrinology
- Metabolism
- Molecular Biology
Background:
- Growth hormone (GH) and leptin are key hormones regulating body fat and metabolism.
- The precise interaction between GH and leptin signaling pathways remains incompletely understood.
Purpose of the Study:
- To investigate the direct effects of GH on fat mass and leptin expression.
- To explore the impact of leptin on GH secretion.
- To elucidate the interplay between GH and leptin in metabolic regulation.
Main Methods:
- Administration of GH to fatty Zucker rats and assessment of body fat percentage and leptin mRNA levels in different fat tissues.
- Treatment with IGF-I in rats.
- Measurement of serum leptin, IGF-I, and urinary C-peptide in acromegaly patients and normal subjects.
- In vitro and in vivo studies on the effect of leptin on GH secretion from pituitary cells and rats.
Main Results:
- GH administration reduced body fat percentage and leptin mRNA levels in epididymal fat tissue.
- IGF-I treatment did not affect body fat or leptin mRNA.
- Acromegaly patients exhibited lower serum leptin levels compared to controls with similar body fat.
- Leptin did not directly alter GH-releasing hormone (GRH) induced GH secretion in vitro or in vivo.
Conclusions:
- GH directly interacts with visceral adipose tissue, reducing fat mass and leptin expression.
- GH's effect on leptin appears to be tissue-specific.
- Leptin may influence GH secretion indirectly via hypothalamic regulation (GRH or somatostatin).
- GH and leptin exhibit a complex interaction, with leptin potentially serving as a marker for this relationship.
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