Peripheral plasma levels of progesterone, oestradiol-17 , oestrone, testosterone, androstenedione and chorionic gonadotrophin during pregnancy in the marmoset monkey, Callithrix jacchus

Abstract

Concentrations of LH[lutropin]/CG [chorionic gonadotropin], androstenedione and testosterone rose in early pregnancy to maximum values at 6-10 wk. Thereafter LH/CG levels declined and androstenedione and testosterone levels remained at plateau values or declined until term. Progesterone, estradiol-17.beta. and estrone increased after ovulation and remained high throughout pregnancy. At 12 wk, when LH/CG levels were falling, progesterone and estradiol rose well above the luteal-phase levels which were maintained for the first 12 wk. Progesterone declined in the 2 wk before birth, while estradiol and estrone remained high. Pregnancies of an unknown stage were dated by reference to a graph of uterine diameter, measured by abdominal palpation, in animals at known times after conception. Measurement of progesterone concentrations during the conception cycle gave more accurate dating and showed that the gestation length was 144 days.