Elevated cyclin D1 expression is governed by plasma IGF‐1 through Ras/Raf/MEK/ERK pathway in rumen epithelium of goats supplying a high metabolizable energy diet. Issue 6 (31st December 2012)

• Record Type: Journal Article
• Authors: Lu, J.; Zhao, H.; Xu, J.; Zhang, L.; Yan, L.; Shen, Z.
• Is Part Of: Journal of animal physiology and animal nutrition. Volume 97:Issue 6(2013:Dec.)
• Page Start: 1170
• Page End: 1178
• Publication Date: 2012-12-31
• Subjects: Animal nutrition -- Periodicals; Feeds -- Periodicals; 636.085
• DOI: 10.1111/jpn.12026
• Languages: English
• ISSNs: 0931-2439

Abstract

<abstract abstract-type="main" id="jpn12026-abs-0001"> <title>Summary</title> <p>The objective of this study was to explore the underlying mechanism of insulin‐like growth factor 1 (IGF‐1)–caused cell proliferation of rumen epithelium in goats fed a high metabolizable energy (ME) diet. In this study, young goats were fed either a low ME [LL, <italic> n</italic> = 9, ME: 0.57 MJ/kg^0.75/day] or high ME [HL, <italic> n</italic> = 9, ME: 1.00 MJ/(kg^0.75/day)] diet for 42 day. The time duration of G₁‐phase was shortened as a result of enhanced expression of cyclin D1 mRNA in the HL group (p &lt; 0.05). It was suggested that a high ME diet promoted cell transition from G₀/G₁ to S‐phase via cyclin D1. The level of phosphorylation of ERK was higher in HL than LL group (p &lt; 0.05). In cell culture, the ERK was phosphorylated by IGF‐1 treatment. The proliferative effects of insulin‐like growth factor 1 (IGF‐1, 25 ng/ml) on [³H] thymidine (TdR) incorporation into DNA and on cyclin D1 protein expression of rumen epithelial cells were inhibited by PPP (the inhibitor of type 1 IGF receptor) (p &lt; 0.05) and ERK inhibitor (p &lt; 0.05) <italic>in vitro</italic>. Thus, IGF‐1 up‐regulated cyclin D1 expression and accelerated G₁‐phase progression in the cell cycle through Ras/Raf/MEK/ERK pathway in rumen epithelium of goats.</p> </abstract>