Is insulin-like growth factor gene expression modulated during cardiac hypertrophy?

Susan M. Czerwinski, Jan Novakofski, Peter J. Bechtel

Research output: Contribution to journalArticle

Abstract

The goal of this study was to examine the relationship between work-induced cardiac hypertrophy and insulin-like growth factor-I and -II (IGF-I and -II) mRNA expression in adult female SpragueDawley rats. Increased cardiac work was induced by coarctation, which involved placing a constricting silk ligature around the abdominal aorta to increase peripheral resistance. Cardiac hypertrophy was determined by measuring in vivo left ventricular protein synthesis rates. There was a rapid increase in left ventricular weight (LV) [both absolute and relative to body weight (mg tissue . 100 g−1 body weight)] following the coarctation surgery. By the third day following coarctation, LV weight was increased approximately 20% and reached 24% by the 10th day as compared with controls. Protein synthesis rates increased dramatically, reached a peak level at 3 d (133% . d−1) compared with 29%KS . d−1 in the sham operated group and then began to slowly decrease toward control rates. The fractional synthesis rates of total protein in the LV were unchanged 1 d post-surgery. IGF-I mRNA content in the LV decreased to approximately 38% below the control content at day 1. However, by 3 d post-surgery IGF-I mRNA content increased to 30-50% above controls, were 31% above control by day 7, and remained elevated thereafter. On the other hand, IGF-II mRNA content remained constant throughout the 10 d post-surgery. Work-necessitated increase in cardiac protein mass may be mediated, in part, by a local autocrine/paracrine production of IGF-I.

Original languageEnglish (US)
Pages (from-to)495-500
Number of pages6
JournalMedicine and Science in Sports and Exercise
Volume25
Issue number4
DOIs
StatePublished - Apr 1993

Keywords

  • Coarctation
  • Heart
  • Igf
  • Work-induced growth

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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