Direct measurements of urinary estrone conjugates during the normal menstrual cycle of the gorilla (Gorilla gorilla)

Abstract

A direct immunoassay for urinary estrone conjugates (estrone sulfate and estrone glucuronide) was used to assess the preovulatory estrogen rise in normal gorilla menstrual cycles. Immunoreactive estrone conjugates in samples concomitantly assessed for total estrogen immunoreactivity reflected similar profiles throughout the cycle; however, the speed and resolution of the direct assay for conjugates indicate this method to be more accurate in monitoring ovulation than the measurement of total immunoreactive estrogens. In a single conceptive ovarian cycle, urinary estrone conjugate continued to rise in the luteal phase, indicating that this test may also be useful for detecting early pregnancy. The application of this technique provides clear profile of ovarian function in gorillas as well as in other primate species.