Prolonged but not short negative energy condition restored corticoadrenal leptin sensitivity in the hypothalamic obese rat.
OBJECTIVE
We have reported that neonatal treatment with monosodium L-glutamate (MSG), which causes damage to the arcuate nucleus, leads to severe hyperleptinemia and reduced adrenal leptin receptor (ob-Rb) expression in adulthood. As a result, rats given MSG neonatally display corticoadrenal leptin-resistance, a defect that is overridden by normalization of corticoadrenal hyperfunction. The aim of the present study was to determine whether negative energy conditions could correct corticoadrenal cell dysfunction in rats given MSG neonatally.


METHODS
Normal (CTR) and MSG-treated female rats were subjected to food removal for 1-5 days, or prolonged (24-61 days) food restriction (FR). Plasma levels of several biomarkers and in vitro corticoadrenal function were evaluated following starvation or FR.


RESULTS
Fasting for 1-5 days reduced plasma leptin levels in CTR and MSG rats, compared to levels in the respective groups fed ad libitum(p < 0.05), but adrenal leptin-resistance was unchanged. With prolonged FR, isolated adrenal cells from MSG rats became sensitive to leptin, which lowered ACTH-induced glucocorticoid release. This restoration of leptin response was associated with normalization of adrenal ob-Rb gene expression.


CONCLUSIONS
Dietary restriction in some leptin-resistant obese phenotypes may normalize adrenocortical function.
Perello
Mario
M
Neuroendocrine Unit, Multidisciplinary Institute on Cell Biology (CONICET-CICPBA), La Plata, Argentina.
Castrogiovanni
Daniel
D
Giovambattista
Andrés
A
Gaillard
Rolf C
RC
Spinedi
Eduardo
E
D000302:Adrenal Cortex / Q000187:drug effects* / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001798:Blood Proteins; D001835:Body Weight; D003345:Corticosterone / Q000378:metabolism; D002149:Energy Intake / Q000502:physiology*; D005260:Female; D005508:Food Deprivation / Q000502:physiology; D007031:Hypothalamus / Q000378:metabolism*; D020738:Leptin / Q000097:blood* / Q000494:pharmacology; D008297:Male; D009765:Obesity / Q000378:metabolism*; D009929:Organ Size; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D054411:Receptors, Leptin / Q000235:genetics; D012970:Sodium Glutamate / Q000494:pharmacology*; D013997:Time Factors; D014280:Triglycerides / Q000097:blood
D001798:Blood Proteins; D020738:Leptin; D012333:RNA, Messenger; D054411:Receptors, Leptin; D014280:Triglycerides; D000324:Adrenocorticotropic Hormone; D012970:Sodium Glutamate; D003345:Corticosterone