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CNS Ghrelin and leptin have opposing functions for the regulation of food intake and bone formation in rats
Author(s) -
Li Qiang,
Rayalam Srujana,
Ambati Suresh,
Hartzell Diane L,
DellaFera Mary Anne,
Hamrick Mark W,
Baile Clifton A
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a461-d
Subject(s) - leptin , ghrelin , endocrinology , medicine , bone marrow , leptin receptor , adipose tissue , stromal cell , downregulation and upregulation , receptor , diet induced obese , chemistry , insulin , obesity , gene , insulin resistance , biochemistry
We tested the hypothesis that centrally administered ghrelin modulates bone formation. Rats implanted with lateral cerebroventricular (ICV) cannulas received control (aCSF), 5 μg leptin (L5), 20 (G20), or 100 pmol (G100) ghrelin, twice daily for 5 days (N=6/trt). Food intake was increased by G100 (18%, p<.05) & decreased by L5 (52%, p<.001). Weight gain was decreased by L5 (p<.001) & increased by G20 (p<.05) & G100 (p<.001). Fat pad weights were decreased by L5 (p<.05) & increased by G100 (p<.05). L5 decreased serum glucagon (69%, p<.01) & leptin (68%, p<.01) levels. Insulin level was decreased by L5 (81%, p<.01) & increased by G100 (70%, p<.05). Adipose tissue apoptosis was increased by L5 (125%, p<.05). Total RNA was extracted from non‐adherent & adherent femoral marrow cultured cells. RT‐PCR showed G20 upregulated marrow mRNA expression of CASP2, MMP11, MADH1, DLK1 by 93% (p<.01), 169% (p<.05), 114% (p<.05) & 173% (p<.05) only in non‐adherent cells. Gene expression was not significantly changed by L5. We conclude that ICV leptin has minimal effect on femoral marrow gene expression in leptin‐replete rats. Non‐adherent cells, mostly bone marrow macrophages had different gene expression responses to the treatment from adherent bone marrow stromal cells. Ghrelin acting on brain receptors has an effect on femoral marrow gene expression. Supported in part by the GA Research Alliance Eminent Scholar endowment held by CAB.