Investigations of the past twelve years provide much new information concerning the regulation of growth and of secretion in the mammary glands. Both growth and secretion are controlled mainly by hormones, but quite different hormones are involved in these two wholly distinct sets of processes. The anterior lobe of the pituitary exercises a direct control (through its lactogenic hormone, prolactin) over milk secretion; in addition it exercises an indirect control (through estrogen, progesterone and possibly other sterols) and perhaps also a direct control (through a mammogenic pituitary hormone) over the development and growth of the mammary glands.
THE LACTOGENIC HORMONE
The Lactogenic Response.—
Stricker and Grüter demonstrated in 1928-1929 that a factor or combination of factors directly essential to lactation is produced by the anterior lobe of the pituitary. Their results were confirmed first by Corner in 1930 and thereafter extended to various species by Nelson and Pfiffner, Turner