The endocrines govern the physiology of reproduction from beginning to end; spermatogenesis, ovogenesis, maturation of the ovum, ovulation, fertilization, preparation of the endometrium for nidation, implantation of the fertilized ovum, placentation, maintenance of pregnancy, development of the fetus, birth and lactation—all are dependent on hormones initiated and controlled by the anterior hypophysis.
The definite suspicion that something in the blood accounted for the phenomena which occurred when the ovaries were removed and a return to normal followed transplantation of ovarian tissue—this was the real inception, even if not the first hint, of the endocrine idea. Then the search for the mysterious substance began, fruitless as to conclusions for many years but very rich in laying the foundations for our knowledge, limited though it is, of the physiology of reproduction.
One needs only to mention a few who placed stones in this foundation, which made the recent great advancements possible, and
LITZENBERG JC. THE ENDOCRINES IN RELATION TO STERILITY AND ABORTION. JAMA. 1937;109(23):1871-1873. doi:10.1001/jama.1937.02780490009003