Open AccessBlunted hypothalamic ghrelin signaling reduces diet intake in rats fed a low‐protein diet in late pregnancy
Author(s) -
Gao Haijun,
Sisley Stephanie,
Yallampalli Chandra
Publication year - 2015
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.12629
Subject(s) - ghrelin , pregnancy , endocrinology , medicine , hypothalamus , protein diet , biology , hormone , body weight , genetics
Diet intake in pregnant rats fed a low‐protein ( LP ) diet was significantly reduced during late pregnancy despite elevated plasma levels of ghrelin. In this study, we hypothesized that ghrelin signaling in the hypothalamus is blunted under a low‐protein diet condition and therefore, it does not stimulate diet intake during late pregnancy. Female Sprague–Dawley rats were fed a normal ( CT ) or LP diet from Day 1 of pregnancy. On Day 21, 0.5 μ g ghrelin was given into the third ventricle ( ICV ). Diet and water intake at 30, 60, and 120 min after ICV injection was measured. Hypothalami were dissected and analyzed for expression of genes related to appetite regulation ( Npy , Agrp , Pomc and Cart ) and phosphorylation of AMPK and ACC proteins (downstream proteins of ghrelin receptor activation). Results include: In response to ICV injection of ghrelin, (1) diet intake was significantly lower in LP compared to CT rats; (2) water intake was not affected in LP rats; (3) expression of Npy and Agrp, but not Pomc and Cart, were higher in the hypothalamus of LP compared to CT rats; (4) the abundance of phosphorylated AMPK and the ratio of phosphorylated to total AMPK , but not the abundance of total AMPK , were lower in LP compared to CT rats; (5) the abundance of phosphorylated ACC , but not total ACC , was lower in LP rats. These findings suggest that blunted ghrelin signaling in the hypothalamus of pregnant rats fed a LP diet leads to reduced diet intake and exacerbates gestational protein insufficiency.