STUDIES ON THE PHYSIOLOGY OF REPRODUCTION IN BIRDS

Abstract

The response in doves and pigeons of the 2 dorsolateral areas of the crop (which normally enlarge at the end of the brooding period and then secrete the "crop-milk" fed to the young) to the several pituitary hormones was tested in 108 doves and pigeons, including 33 controls, 56 birds injected with anterior lobe extracts, 10 with posterior lobe extracts, and 9 with luteinizing hormone from pregnant urine. Other hormones and substances had earlier been found ineffective. The luteinizing hormone, the posterior lobe extracts and one (commercial) anterior-lobe extract (antuitrin) were without effect on the crop-glands; 3 other anterior lobe extracts (1 growth hormone, 1 sex maturity hormone, 1 glycerin extract) pro- duced enlarged and functioning crop glands without exception in 29 birds tested, including nestling young and 16 [male][male]. All the effective extracts were known to contain the sex maturity hormone; all probably contained at least small amounts of the growth principle. Which anterior-lobe hormone influenced the crop-gland was not determined. A previously effective preparation tested, after heating for 13 hrs., at 99[degree] C, on 4 birds had no effect on the crop glands. The crop-gland response was obtained in one pigeon after section of the nerves supplying the area, and is therefore not regulated or conditioned by the nerves. The authors conclude that, if this is a specific response to the growth hormone, it is the best method of testing and standardizing that hormone.