Abstract
Treatment of sexually immature pullets with testosterone propionate so as to evoke changes in combs and wattles similar to normal puberal changes did not affect liver weight or liver content of nucleic acids. Estradiol benzoate, or estradiol benzoate plus testosterone propionate, increased liver weight and total liver pentose nucleic acid, and slightly increased liver desoxypentose nucleic acid. Chemical evidence is adduced in support of the view that the increase of liver crude protein caused by estrogen is a consequence of cellular hypertrophy accompanied by a slight degree of hyperplasia. The ratio RNAP: DNAP was relatively high in the liver of the young chicken, but declined somewhat during the first 12 weeks. With the onset of reproductive activity, the ratio RNAP: DNAP increased in the livers of the females but did not show a similar tendency in the males. The results suggest that there is a sexual differentiation in the nucleic acid content of the livers of the mature fowl, and that this is reasonably attributable to endogenous estrogen activity. Data are presented in confirmation of the reported effect of estrogen in increasing serum or plasma nucleic acid in the fowl, androgen being without any such effect.