Abstract
Chromatophorotropic hormone is extracted from 10-20 ml of human blood and the hormone content is estimated on intact green-adapted tree frogs (Hyla arborea). The test appears to be specific for chromatophorotropic hormone. The common biogenic amines and amino acids as well as hormones did not produce the chro-matophore reaction in Hyla. In comparison to other frogs (Rana) the Hyla test proved to be superior due to its specificity and easy performance. A normal person has a level of less than 50 frog units per liter blood. There is no difference between normal males and females. Chromatophorotropic hormone in the blood is increased in the following conditions: hypoadrenal-ism, low 17-Ks levels, hyperadrenalism associated with pituitary basophilia, circulatory stress as in recent myocard infarction, pregnancy (about 20% of the cases), obstetrical stress, gynecological disturbances, dermatological conditions, psychic stress, operational stress and shock, and ophthalmic conditions.