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Direct modification of somatotrope function by long-term leptin treatment of primary cultured ovine pituitary cells.
- Source :
-
Endocrinology [Endocrinology] 2001 Dec; Vol. 142 (12), pp. 5167-71. - Publication Year :
- 2001
-
Abstract
- Leptin is produced primarily in adipocytes and regulates body energy balance. A close link between leptin and pituitary hormones, including GH, has been reported. The mechanisms employed by leptin to influence somatotropes are not clear, however. Here we report a direct action of recombinant ovine leptin on primary cultured ovine somatotropes by analyzing the levels of mRNA encoding for GH or the receptors for GHRH (GHRH-R) and GH-releasing peptides (GHRP). Treatment of ovine somatotropes with leptin (10(-7)-10(-9) M) for 1-3 d reduced the mRNA levels encoding GH and GHRH-R, but increased GHRP receptor mRNA levels in a time- and dose-dependent manner. Three-day treatment of cells with leptin decreased the GH response to GHRH stimulation, but the GH response to GHRP-2 stimulation was increased. The combined effect of GHRH and GHRP-2 on GH secretion was not altered by treatment of the cells with leptin. These results demonstrated a direct action of leptin on ovine pituitary cells, leading to a reduced sensitivity of somatotropes to GHRH. It is also suggested that GHRP may be useful to correct the decrease in GHRH-induced GH secretion by leptin.
- Subjects :
- Animals
Cells, Cultured
Growth Hormone-Releasing Hormone biosynthesis
Human Growth Hormone biosynthesis
Pituitary Gland, Anterior cytology
Receptors, Leptin
Receptors, Neuropeptide biosynthesis
Receptors, Pituitary Hormone-Regulating Hormone biosynthesis
Sheep
Time Factors
Human Growth Hormone metabolism
Leptin pharmacology
Pituitary Gland, Anterior drug effects
Pituitary Gland, Anterior metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0013-7227
- Volume :
- 142
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- Endocrinology
- Publication Type :
- Academic Journal
- Accession number :
- 11713211
- Full Text :
- https://doi.org/10.1210/endo.142.12.8559