John Jacob Abel to successfully isolate the neutral base of epinephrine by adding ammonium to highly concentrated extract, a method Abel himself tried but failed due to the use of low concentration of extract. After Takamine's success, Abel himself remarked, with great candor, "The efforts of years on my part in this once mysterious field of suprarenal, medullary biochemistry, marred by blunders as they were, eventuated, then, in the isolation of the hormone not in the form of the free base but in that of its monobenzoyl derivative." Together with L.G. Rowntree and B.B. Turner, Abel devised what they called a "vividiffusion" apparatus,
John Leonora to have an activity indistinguishable from the isolated parotid hormone or the gene-expressed hormone. Meanwhile, it was discovered that the acinar cells of the parotid glands were apparently the source of the parotid hormone. Preliminary research suggested the parotid hormone not only regulates dental structures but also influences insulin secretion by the pancreas. These systemic effects have yet to be followed up. As Leonora stated in an undated letter, "I anticipate finding receptors [for the parotid hormone] in the odontoblasts in teeth, osteocytes in bone matrix, Islets of Langerhans…" John Leonora John Leonora (January 30, 1928 - February 17, 2006)