Circulating and excreted hormones during the ovarian cycle in the cotton-top tamarin, Saguinus oedipus

Five parous, cycling cotton‐top tamarin females were used to compare circulating and urinary profiles of the major reproductive hormones during the ovarian cycle. Blood samples were collected on unanesthetized, hand restrained females three times per week for 25 days and first morning void urine was collected daily for 30–40 days including the serum sampling period. Serum and urine samples were analyzed for estrone, estradiol, and bioactive LH. Additionally, serum was analyzed for progesterone and urine for estrone conjugates (E1G) and immunoreactive LH. Both serum and urinary hormonal profiles revealed ovarian cyclicity in four females; the fifth one stopped cycling during the study. All hormones were referenced to the urinary immunoreactive LH peak. Urinary estrone conjugates followed similar profiles to serum progesterone. Progesterone levels increased two‐ to threefold on the day of the urinary immunoreactive LH peak. Peak levels of circulating bioactive LH occurred on the same day or the day preceding the urinary bioactive and immunoreactive LH peak for all four cycling females. Serum estradiol levels rose during the follicular phase and peaked prior to or on the day of the urinary LH peak while urinary estradiol levels did not rise until the day of the urinary LH peak. Serum and urinary estrone levels did not rise until the day of the urinary LH peak and remained high throughout the luteal phase. The measurement of urinary LH corresponded well with serum LH, establishing urinary LH as an important hormone for monitoring the ovulation in the tamarin. The highest circulating estradiol concentrations were found in the follicular phase of the cycle, but estradiol did not appear in urine during the follicular phase of the cycle. Elevated estrone levels occur during the luteal phase following the progesterone pattern, and therefore elevated urinary concentrations of estrone and estrone conjugates may be indicative of luteal function. © 1993 Wiley‐Liss, Inc.