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,
Melanin-concentrating hormone when diet is controlled. It has been postulated that MCH has a modulatory role with the release of Luteinizing Hormone (LH) either by directly interacting acting on the pituitary gland or indirectly by affecting Gonadotropin-releasing hormone (GNRH) in the hypothalamus. Estrogen seems to be necessary in order for MCH to affect reproduction. Though MCH was initially discovered for its role of determining the pigmentation in fish, trying to determine MCH's role in skin pigmentation in mammals has been much more difficult to determine. However, MCHR1 has been found in human melanocytes and some melanoma cells, so MCH is able to