Plasma progesterone levels throughout the ovarian cycle of the common marmoset (Callithrix jacchus)

Abstract

To determine the ovarian cycle length in the common marmoset, plasma progesterone levels were estimated by radioimmunoassay. The total cycle length was 26.2±2.4 days (N=8). The preovulatory phase lasted for 9.5±2.2 days as assessed by plasma progesterone levels which were below 10 ng/ml throughout this period. The duration of the postovulatory phase, when plasma progesterone levels were more than 10 ng/ml, was 16.6±1.1 days.