QUANTITATIVE ASSAY OF THE MELANOPHORE DISPERSING HORMONE DURING THE DEVELOPMENT OF THE CHICKEN PITUITARY1

Abstract
Quantitative assays of the melanophore dispersing hormone of the pars anterior of chicken pituitaries were made during embryonic and post-natal development. Hypophysectomized Anolis lizards were used as test animals. Long before the onset of histological differentiation of the pituitary this hormone makes its 1st appearance on the 5th day of incubation and can be assayed quantitatively after the 7th day. The hormone conc. per unit wt. of pituitary rises rapidly during the 2d half of the incubation period and does not change significantly during the post-natal development. The apparent increase of hormone after hatching may be accounted for by the growth or increase of wt. of the gland.