Alcohol Suppresses Insulin-Like Growth Factor-1 Gene Expression in Prepubertal Transgenic Female Mice Overexpressing the Bovine Growth Hormone Gene

Authors

  • Vinod K. Srivastava,

    Corresponding author
    1. Department of Veterinary Anatomy and Public Health (VKS, RKD, JKH, WLD), Texas A&M University, College Station, Texas; and Department of Physiology (VC, JAM, AB), School of Medicine, Southern Illinois University, Carbondale, Illinois.
    Search for more papers by this author
  • Robert K. Dearth,

    1. Department of Veterinary Anatomy and Public Health (VKS, RKD, JKH, WLD), Texas A&M University, College Station, Texas; and Department of Physiology (VC, JAM, AB), School of Medicine, Southern Illinois University, Carbondale, Illinois.
    Search for more papers by this author
  • Jill K. Hiney,

    1. Department of Veterinary Anatomy and Public Health (VKS, RKD, JKH, WLD), Texas A&M University, College Station, Texas; and Department of Physiology (VC, JAM, AB), School of Medicine, Southern Illinois University, Carbondale, Illinois.
    Search for more papers by this author
  • Varadaraj Chandrashekar,

    1. Department of Veterinary Anatomy and Public Health (VKS, RKD, JKH, WLD), Texas A&M University, College Station, Texas; and Department of Physiology (VC, JAM, AB), School of Medicine, Southern Illinois University, Carbondale, Illinois.
    Search for more papers by this author
  • Julie A. Mattison,

    1. Department of Veterinary Anatomy and Public Health (VKS, RKD, JKH, WLD), Texas A&M University, College Station, Texas; and Department of Physiology (VC, JAM, AB), School of Medicine, Southern Illinois University, Carbondale, Illinois.
    Search for more papers by this author
  • Andrzej Bartke,

    1. Department of Veterinary Anatomy and Public Health (VKS, RKD, JKH, WLD), Texas A&M University, College Station, Texas; and Department of Physiology (VC, JAM, AB), School of Medicine, Southern Illinois University, Carbondale, Illinois.
    Search for more papers by this author
  • W. Les Dees

    1. Department of Veterinary Anatomy and Public Health (VKS, RKD, JKH, WLD), Texas A&M University, College Station, Texas; and Department of Physiology (VC, JAM, AB), School of Medicine, Southern Illinois University, Carbondale, Illinois.
    Search for more papers by this author

  • Supported by NIH Grants AA-07216 and ESO-9106 (WLD) and HD20001 (AB).

Dr. Vinod K. Srivastava, Department of Veterinary Anatomy and Public Health, Texas A&M University, College Station, TX 77843–4458; Fax: 979–847–8981; E-mail: vsrivastava@cvm.tamu.edu.

Abstract

Background Alcohol (ALC) delays puberty in female rats and alters the development of a normal menstrual pattern in rhesus monkeys. These actions are associated with depressed serum levels of growth hormone (GH), luteinizing hormone and insulin-like growth factor-1 (IGF-1). The mechanism of this ALC-induced depression in IGF-1 is not known, however, could be due to depressed GH and, possibly, to an alteration in the hepatic GH receptor. To assess whether ALC has a direct action at the liver, we used a transgenic mouse model that overexpresses GH, allowing assessment of potential direct actions of ALC on the level of either the GH receptor or the IGF-1–synthesizing machinery within the hepatocyte.

Methods One group of transgenic mice was fed a liquid diet containing ALC. The second group was pair-fed the companion isocaloric control liquid diet. The third group of transgenic mice was fed Lab Chow and water. The fourth group consisted of normal (nontransgenic) littermates fed Lab Chow and water. Animals received their respective diets for 5 days. Mice were killed during their late juvenile stage of development, and tissues and blood collected and frozen.

Results The ALC-fed transgenic mice showed a decrease (p < 0.01) in hepatic IGF-1a and IGF-1b messenger RNA levels compared with transgenic controls, and this paralleled a decrease (p < 0.01) in serum IGF-1. ALC did not alter the circulating levels of bovine GH held constant by the promotor and did not alter mouse GH receptor protein levels as analyzed by Western blotting.

Conclusions Using this transgenic animal model that maintains circulating GH in the presence of ALC, we found that the ability of ALC to suppress prepubertal Igf1 gene expression can also occur independently of any alterations in the level of circulating GH. This direct effect on the hepatocyte is a postreceptor event because the GH receptor protein levels were not altered by ALC exposure.

Ancillary