[Development and control of liver amylo-1,6-glucosidase activity in the fetal rat]

The development of amylo-1,6-glucosidase activity is studied in fetal rat liver. The activity of control fetuses is high on day 17.5, decreases from day 17.5 to day 19.5, and then rises during the next days. In hypophysectomised fetuses, the increase of the activity is suppressed but not the decrease. Moreover, if the mother is adrenalectomized the decrease and the increase are abolished in hypophysectomised fetuses. Growth hormone administration is quite effective in preventing the decrease in enzyme activity but cortisol treatment does not prevent it. In contrast, cortisol produces a precocious decrease of the activity in intact fetuses. These findings suggest that during fetal life, two hormonal regulation mechanisms are involved in the regulation of amylo-1,6-glucosidase activity: cortisol has a repressive effect on the enzymic activity while growth hormone acts as an inducer.