title: Dexamethasone treatment in vivo counteracts the functional pancreatic islet alterations caused by malnourishment in rats.
abstract: The effects of dexamethasone (Dex) on the metabolic parameters, peripheral insulin, and glucose sensitivity in vivo as well as on islet function ex vivo of rats submitted to low-protein diet were analyzed. Dexamethasone (1.0 mg/kg body weight) was administered intraperitoneally daily to adult Wistar rats fed on a normal-protein diet or low-protein diet (LPD) for 5 days, whereas control rats fed on a normal-protein diet or low-protein diet (LP) received saline alone. At the end of the experimental period, LP rats showed a significant reduction in serum insulin, total serum protein, and serum albumin levels compared with rats fed on a normal-protein diet (P<.05). All these parameters tended to be normalized in LPD rats (P<.05); furthermore, these rats exhibited increased serum glucose and nonesterified fatty acid levels compared with LP rats (P<.05). Rats submitted to the low-protein diet demonstrated normal peripheral glucose sensitivity and improved peripheral insulin sensitivity, which was reversed by Dex treatment. A reduced area of islets from LP rats was partially recovered in LPD rats (P<.05). At 16.7 mmol/L glucose, insulin secretion from LPD islets was also partially recovered and was significantly higher than that from LP islets (P<.05). In conclusion, induction of insulin resistance by Dex treatment reverses most of the metabolic alterations in rats submitted to a low-protein diet. In addition, several islet functions were also improved by Dex, confirming the plasticity of pancreatic islets in adverse conditions.
authors.affiliation: Department of Physiology and Biophysics, Institute of Biology, State University of Campinas (UNICAMP), 13083-970 Campinas, SP, Brazil.
authors.forename: Vanessa A G
authors.initials: VA
authors.lastname: Giozzet
authors.forename: Alex
authors.initials: A
authors.lastname: Rafacho
authors.forename: Antonio C
authors.initials: AC
authors.lastname: Boschero
authors.forename: Everardo M
authors.initials: EM
authors.lastname: Carneiro
authors.forename: José R
authors.initials: JR
authors.lastname: Bosqueiro
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D003907:Dexamethasone / Q000494:pharmacology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism* / Q000473:pathology; D008297:Male; D011488:Protein Deficiency / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D003907:Dexamethasone