NATURE OF THE PITUITARY FACTOR STIMULATING MAMMARY DUCT GROWTH1

Abstract

THAT the pituitary contains some factor or factors involved in mammary growth is generally accepted. However, as to the exact nature, number and mode of action of such entities there has been debate (Greep and Stavely, 1941; White 1943). The present paper deals with the question of the chemical nature {i.e. protein or lipid) of the pituitary factor responsible for the stimulation of mammary duct growth in the male mouse. Using the male mouse in an assay technique, Lewis and Turner (1938) reported that the drying and defatting of fresh pregnant cattle pituitary with acetone and ether resulted in a60 per cent loss of mammary duct-growth stimulating activity (mammogen I) present in the fresh gland. However, the extraction of fresh tissue with 60 per cent alcohol, followed by precipitation of lactogenic and other protein hormones by adjusting the-pH to 5.7 and increasing the alcohol content to 86 per cent, yielded, upon vacuum distillation, an oily residue containing 90 per cent of the activity of the fresh t...