Multiple consequences of human growth hormone expression in transgenic mice

Area of Science:

• Molecular Biology
• Genetics
• Endocrinology

Background:

• Transgenic animal models are crucial for studying gene function and regulation.
• Growth hormone (GH) plays a vital role in development and metabolism.
• Understanding the effects of ectopic hormone gene expression is essential.

Purpose of the Study:

• To investigate gene integration, expression, and phenotypic consequences of a mouse metallothionein I-human growth hormone (mMT I-hGH) fusion gene in transgenic mice.
• To analyze the clinical and pathomorphological alterations associated with hGH transgene expression.
• To compare findings with other GH-transgenic mouse models.

Main Methods:

• Production of transgenic mice via DNA microinjection of the mMT I-hGH fusion gene into fertilized oocytes.
• Analysis of gene integration and expression levels.
• Phenotypical, clinical, and pathomorphological examination of transgenic mice.

Main Results:

• Significant increases in body and organ growth were observed in transgenic mice.
• Reduced fertility and a markedly shortened lifespan were noted.
• Predominant pathological findings included lesions in the kidneys, liver, and heart.
• Detrimental side effects were linked to high levels of circulating hGH.

Conclusions:

• GH-transgenic mice expressing the hGH transgene exhibit accelerated growth but suffer from reduced fertility and lifespan.
• Ectopic expression of the hGH transgene leads to significant pathological alterations.
• These mice serve as a valuable model for studying the effects of hormone gene overexpression and circumventing endogenous feedback mechanisms.