Effect of central angiotensin II on body weight gain in young rats.
Systemic infusion of ANG II decreases body weight and food intake and increases energy expenditure. We recently reported that young rats receiving a 1-week intracerebroventricular (i.c.v.) infusion of angiotensin II (ANG II) exhibited decreased body weight compared to control. The aim of the present investigation was to determine if chronic i.c.v. infusion of ANG II also decreases food intake and increases energy expenditure. Young rats were infused with i.c.v. 0.9% saline or ANG II (16.7 or 4.2 ng/min) for at least 10 days and body weight and food intake were monitored daily. Pair-fed rats had the same daily food intake as the ANG II-infused rats. The i.c.v. ANG II decreased body weight gain and food intake. The decrease in weight gain was greater than in the pair-fed groups. The expression of mRNA for uncoupling protein-1 (UCP-1) in BAT was increased significantly in the ANG II-infused rats compared to the pair-fed animals. Subcutaneous infusion of ANG II at the same doses used for i.c.v. infusion had no effect on body weight or food intake. The expression of CRH mRNA in the paraventricular nucleus was not increased in the ANG II-infused rats. These data are consistent with the idea that i.c.v. ANG II decreases body weight gain in young rats, in part, by decreasing food intake and, in part, by increasing thermogenesis (although via a CRH-independent mechanism). This central effect of ANG II may contribute to or complement the effect of peripheral ANG II on body weight.
Porter
James P
JP
Department of Physiology and Developmental Biology and the Neuroscience Center, Brigham Young University, Provo, UT 84602, USA. james_porter@byu.edu
Anderson
Jared M
JM
Robison
Reid J
RJ
Phillips
Adam C
AC
D002001:Adipose Tissue, Brown / Q000378:metabolism; D000804:Angiotensin II / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects* / Q000502:physiology; D002352:Carrier Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects*; D004734:Energy Metabolism / Q000187:drug effects; D017403:In Situ Hybridization; D007276:Injections, Intraventricular; D007279:Injections, Subcutaneous; D007473:Ion Channels; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D024101:Mitochondrial Proteins; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D000071256:Uncoupling Protein 1; D014662:Vasoconstrictor Agents / Q000008:administration & dosage / Q000494:pharmacology*; D015430:Weight Gain / Q000187:drug effects* / Q000502:physiology
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; C000604373:Ucp1 protein, rat; D000071256:Uncoupling Protein 1; D014662:Vasoconstrictor Agents; D000804:Angiotensin II