Epidermal growth factor measurements in mouse plasma: method, ontogeny, and sex difference

Area of Science:

• Endocrinology
• Developmental Biology
• Mouse Physiology

Background:

• Epidermal Growth Factor (EGF) plays a crucial role in cellular processes.
• Understanding EGF's ontogeny and regulation is vital for developmental studies.
• Previous studies may have overestimated mouse EGF levels due to contamination.

Purpose of the Study:

• To quantify mouse plasma and submandibular gland (SMG) epidermal growth factor (EGF) levels across different ages.
• To investigate the influence of sex and testosterone on EGF concentrations.
• To establish accurate baseline EGF levels in mice, minimizing contamination.

Main Methods:

• Utilized a highly sensitive radioimmunoassay for mouse plasma and serum EGF.
• Collected blood from the inferior vena cava to avoid neck blood contamination.
• Measured EGF in plasma and SMG tissue from mice at various developmental stages.

Main Results:

• Serum EGF levels in mice showed distinct developmental patterns, reaching adult values at different times in males and females.
• Adult male mice exhibited twofold higher serum EGF levels compared to adult females.
• Submandibular gland (SMG) EGF levels displayed a different ontogeny than serum EGF, with no adult correlation.
• Testosterone treatment increased female serum EGF but did not reach male levels.

Conclusions:

• Mouse serum EGF levels are significantly influenced by age and sex, with males having higher concentrations.
• SMG-EGF ontogeny differs from serum EGF, and no direct correlation exists in adults.
• Accurate measurement techniques are essential, as previously reported mouse EGF levels may have been inflated by contamination.