Factor supprossing alpha1 fetoprotein production.

The injection of sera of adult mice or of a 20% extract of small and large intestine, liver, kidney, spleen, thymus, and lungs of adult mice suppressed the alpha1 fetoprotein production in syngeneic newborn recipients. Extracts of the striated muscles of adult mice had a meager inhibitory effect. Extracts of mouse embryonic intestine and those of the while embryo without the gastrointestinal tract had almost negligible amounts of suppressing factor. The possible role of humoral factors regulating the synthesis of embryonic antigens for the control of tumor growth was discussed author...