Diet-Induced Obesity and Ghrelin Effects on Pituitary Gonadotrophs: Immunohistomorphometric Study in Male Rats
Objective: The close relationship between energy metabolism, nutritional state, and reproductive physiology suggests that nutritional and metabolic disorders can disrupt normal reproductive function and fertility. Considering the importance of leptin and ghrelin effects in regulation of the hypot...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Royan Institute (ACECR), Tehran
2016-02-01
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| Series: | Cell Journal |
| Subjects: | |
| Online Access: | http://celljournal.org/web/journal/article/1224/download |
| Summary: | Objective: The close relationship between energy metabolism, nutritional state, and
reproductive physiology suggests that nutritional and metabolic disorders can disrupt
normal reproductive function and fertility. Considering the importance of leptin and
ghrelin effects in regulation of the hypothalamic-pituitary-gonadal axis, the objective
of this study was to investigate the influence of obesity and centrally applied ghrelin
on immunohistochemical appearance and quantitative morphology of the pituitary
follicle-stimulating hormone (FSH) and luteinizing hormone (LH) producing cells in
adult male rats.
Materials and Methods: In this experimental study, animals were given two different
diets: normal-fat (NF) and high-fat (HF), for 4 weeks, corresponding to normal
and positive energy balance (n=2×14), respectively. Each group was subsequently
divided into two subgroups (n=7) receiving intracerebroventricular (ICV) injections of
either ghrelin [G, 1 μg/5 μL phosphate buffered saline (PBS)] or vehicle (5 μL PBS,
control group) every 24 hours for five consecutive days.
Results: Morphometric analyses showed that in HF control group, the percentage of
FSH cells per unit volume of total pituitary gland tissue (in μm3), i.e. volume density
(Vvc), was increased (P<0.05) by 9.1% in comparison with the NF controls. After
ICV treatment with ghrelin, volume (Vc) and volume density (Vvc) of FSH cells in
ghrelin+NF (GNF) and ghrelin+HF (GHF) groups remained unchanged in comparison
with NF and HF controls. Volume of LH cells in HF control group was increased by
17% (P<0.05), but their Vvc was decreased by 8.3% (P<0.05) in comparison with
NF controls. In GNF group, the volume of LH cells increased by 7% (P<0.05), in
comparison with the NF controls, but in GHF group, the same parameter remained
unchanged when compared with HF controls. The central application of ghrelin decreased
the Vvc of LH cells only in GNF group by 38.9% (P<0.05) in comparison with
the NF control animals.
Conclusion: The present study has shown that obesity and repetitive ICV administration
of low doses of ghrelin, in NF and HF rats, modulated the immunohistomorphometric
features of gonadotrophs, indicating the importance of obesity and ghrelin in regulation of
the reproductive function. |
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| ISSN: | 2228-5806 2228-5814 |