Concentration of Androgens in Systemic Plasma of Rats, Guinea Pigs, Salamanders and Pigeons

Abstract

The concentrations of androstenedione, testosterone and de-hydroepiandrosterone have been measured in systemic plasma of adult male specimens of domesticated rats, guinea pigs and pigeons and the salamander Necturus. Values for normal human subjects are given for comparison. Striking differences were observed in testosterone concentration among the various species. Several interpretations of this finding are discussed. The androgen content of plasma of sexually mature rats was compared with that of a few pools of plasma from immature animals. The data indicate that the testo-sterone/androstenedione ratio increases at puberty in the rat.