Plasma testosterone concentration and binding in the chimpanzee; effect of age.

Abstract

Plasma testosterone concentration was 4.7 ± 6.2 SD, 14.7 ± 1 1.8 SD, 263 ± 144 SD and 495 ± 143 SD ng/100 ml in infant, juvenile, adolescent, and adult chimpanzees, respectively, as measured by competitive protein binding. The water blank of the method was 4.0 ± 2.9 SD ng/100 ml and was not subtracted. Plasma testosterone binding affinity and capacity as measured in concomitant samples by a Sephadex, equilibrium dialysis method was significantly less (p < 0.001) in adult chimpanzees than in any of the other age groups. Both the range of plasma testosterone and the fall in testosterone binding are similar to corresponding measurements reported for human pre- and postpubertal subjects. Estimates of the percent of the total testosterone remaining unbound in prepubertal and postpubertal male chimpanzees are about twice the corresponding values reported for boys and men, respectively. Serum total proteins and globulin were greater in adult than in infant chimpanzees while serum albumin and the albumin/globulin...