Observations on the vitamin metabolism of the common fowl III. The effects of oestradiol dipropionate, testosterone propionate and progesterone injections in immature pullets on the riboflavin content of the magnum

1. The effects of injections of oestradiol dipropionate, testosterone propionate and progesterone in immature pullets have been studied. 2. Oestradiol dipropionate evokes hypertrophy of the oviduct, and increases in serum calcium and serum riboflavin. 3. Testosterone propionate evokes hypertrophy and reddening of the comb and wattles, it acts synergistically with oestradiol dipropionate in evoking hypertrophy of the oviduct. 4. Progesterone antagonizes the effects of oestradiol dipropionate and testosterone propionate on the growth of the oviduct. 5. Progesterone and/or testosterone propionate increase the percentage of free riboflavin in the hypertrophied magnum from 18% of the total vitamin present to 35%.