Mouse epidermal growth factor: light and electron microscopical localisation by immunocytochemical staining.

Epidermal Growth Factor (EGF) has been localised by immuno-staining to granules of the convoluted duct cells of the submaxillary glands of mice. Improved techniques of freeze drying and formaldehyde vapour fixation have resulted in a light microscopical localisation sharper than was achieved by previous methods. EGF has also been identified by electron immunocytochemistry using the unlabelled antibody enzyme method. EGF is present in greater quantities in male mice than in female mice but in pregnant females the level of EGF in the submaxillary gland is equal to that of the male. It declines gradually during the three weeks of lactation. In view of the chemical similarity between mouse EGF and human Urogastrone these improved methods of identification may be useful in the localisation of the human substance.