Identification of the lactogenic compound present in beer.

Lyophylized beer and extracts of plants used to prepare beer have been administered orally to mature virgin rats and intravenously to ewe. After four days of treatment, beta-casein estimated by a radioimmunoassay was present in the mammary glands of the rats to which beer or barley extracts were given. Injections of lyophilised beer, barley or malt extracts triggered the release of prolactin in ewe whereas hop extracts were inactive. The active compound present in beer barley and malt, was insolubilized in 50% ethanol and it is in the aqueous phase in chloroform extraction. The active preparation contained essentially polysaccharides. This suggests that the lactogenic principle belongs to this class of macromolecule.