Shimizu / Poster

Assessment of reproductive status by using urinary hormone evaluation in great apes

Keiko Shimizu, Toshifumi Udono*, Fusako Mitsunaga and Motoharu Hayashi
Primate research Institute, Kyoto University;
*Sanwa Kagaku Kenkyusho, Kumamoto Primate Center;

     Assessing reproductive status is important to the effective management of captive and free-ranging wildlife species. Ovarian function in great apes can be evaluated by estimating the concentrations of hormones in circulation. However, the monitoring of the hormonal changes requires daily blood sampling, a procedure that, in the case of great apes, necessitates anesthesia. The limitations have been alleviated by use of daily urine samples and the direct measurement of urinary estrone conjugates (E1C) and pregnandiol-3-glucuronide (PdG) for monitoring ovarian function by enzyme immuno assay (EIA)s.
     The present study was undertaken to 1) ascertain the usefulness of these methods in evaluating reproductive function in great apes and 2) assess the effects of Norprant implants for contraception on ovarian hormone secretion and genital swelling patterns in female chimpanzee by EIA.
     1) Urine samples were collected daily from the cage floor during ovarian cycles in captive female chimpanzees, orangutan and gorilla. Urine was analyzed for concentrations of E1C and PdG by EIA. A typical preovulatory urinary E1C peak and postovulatory increase in urinary PdG were seen during the menstrual cycles in regularly menstruating chimpanzees and orangutan. However, gorilla, her menstrual cycles had been irregular, showed consistently low E1C and PdG concentrations with no cyclic variation, indicating anovulation.
     Daily urinary E1C and PdG measurements together with observation and reagent strip tests for blood in the urine were found to be useful in assessing the reproductive status of great apes.
     2) Urine samples were collected during one natural cycle before and two cycles following insertion of Norplant implants. Genital swelling data were recorded daily. During Norplant treatment, one female exhibited minimal ovarian activity consistent with anovulation. Hormone data from two females indicated both follicular and luteal activity, suggesting that ovulation may have occurred during Norplant treatment.