Abstract
Summary
It has been shown that appreciable quantities of mammogenic factor are left in initial residue of anterior pituitary gland after extraction of the known hormones by usual technics. This factor was extractable by either a monosodium-disodium phosphate buffer solution or a saline solution. The active factor precipitated from the phosphate buffer system along with phosphate salts after addition of ethanol and butanol and adjusting the pH to 12.5. Phosphate salts were subsequently removed by dialysis, during which mammogenic hormone precipitated out of solution. Active factor was precipitated from saline solution by saturation of solution with NaCl and chilling. Resulting light grey, amorphous powder obtained by phosphate extraction was 223 times more potent in promoting mammary gland growth than progesterone, and contained negligible, if any, lactogenic activity. A highly purified lactogenic preparation assayed for mammogenic activity at the same time was only 1.59 times as potent as progesterone. On this basis the lactogen need contain no more than 0.71% of mammogen to produce the biological response observed.
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