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Effects of central insulin treatment on the mechanisms controlling energy balance in male and female juvenile rats
Author(s) -
KeenRhinehart Erin M,
Liljelund Patricia,
Desai Mina,
Ross Michael G
Publication year - 2009
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.23.1_supplement.1022.1
Subject(s) - orexigenic , endocrinology , medicine , insulin , juvenile , neuropeptide y receptor , obesity , neuropeptide , meal , hormone , saline , biology , receptor , genetics
The incidence of juvenile obesity is increasing at an alarming rate. In adults, central insulin treatment decreases food intake, body weight and hypothalamic orexigenic neuropeptides in a sex dependent manner. Mechanisms regulating energy balance in juvenile animals are inherently different from those in adults due to differences in growth rates and hormonal milieu. Therefore, we sought to determine if central insulin treatment in juvenile rats (21 day old) would have similar effects on energy balance as those reported in adult rats. 24 h food intake was measured after male and female rats were injected with saline, 0.1 or 0.5 U insulin icv just before lights out, and all rats received all treatments in a counterbalanced fashion with 48 h between injections. Additional sets of animals were used to assess the effects of insulin on c‐fos protein expression and NPY mRNA. Insulin treatment increased meal latency, decreased food intake, increased neuronal activation and decreased hypothalamic NPY expression. Unlike previous adult studies, there were no sex differences and decreases in food intake were small (10‐30%) with central insulin treatment. Therefore, central mechanisms regulating juvenile energy balance are significantly different from those in adults, and further study of these mechanisms should generate information to combat the increasing incidence of juvenile obesity. Funded by: NIH 1R01HD054751‐01A2