Hormonal Effects on Phosphorylase Activity and Glycogen Levels in the Rat Ductus Deferens

Abstract

Phosphorylase a and t and the activity ratios in the rat ductus (d.) deferens decreased within 7 days following castration. By 25 days, there was a further decrease in the enzyme activities but not in the ratios. Testosterone treatment of castrated rats reversed these changes in phosphorylase activity. Glycogen levels of the d. deferens were the same in normal and castrated rats. Estradiol injections had no effect on the enzyme activity or the glycogen levels. Epinephrine injected ip into intact males decreased glycogen concentration, phosphorylase a and the activity ratios within 30 min, but not phosphorylase t. Stimulation of d. deferentia in vitro with epinephrine or oxytocin increased phosphorylase α and the activity ratios within 1.5 to 2.0 min, but only in those from castrated males. Omitting glucose from the Krebs-Ringer-bicarbonate medium increased the base level of phosphorylase a activity in the castrated rat ducts. No spontaneous isotonic contractions were observed, but transient rapid contractions occurred in ducts from castrated rats when treated in vitro with epinephrine or oxytocin. Androgen appears to control normal growth and function of the rat d. deferens, but ducts from rats under the influence of male hormone failed to show changes in phosphorylase activity in response to in vitro treatments. (Endocrinology76: 870, 1965)