Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
Prostaglandins were discovered almost forty years ago, but their elucidation physiologically is in its infancy today. It was only in 1957 that the first prostaglandin, PGF1-alpha, was crystallized from sheep seminal vesicles. By 1966, all of the known fourteen natural prostaglandins had been synthesized from commercially available materials. Research data has been compiled at a remarkable rate during the last three to five years.
"Prostaglandins - A Promising Future,"
Iowa State University Veterinarian: Vol. 36
, Article 2.
Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol36/iss2/2