OVARIAN HORMONE CONCENTRATIONS AND GENITAL SWELLING PATTERNS IN FEMALE CHIMPANZEES WITH NORPLANT IMPLANTS

The purpose of this study was to assess the effects of Norplant implan ts on ovarian hormone secretion and genital swelling patterns in femal e chimpanzees. Urine samples were collected during one natural cycle b efore (n=5 females) and one cycle similar to 6 months following (n=7 f emales) insertion of Norplant implants. Genital swelling data were rec orded daily for all seven females. During Norplant treatment, two fema les exhibited minimal ovarian activity consistent with anovulation. Ho rmone data from five subjects indicated both follicular and luteal act ivity, suggesting that ovulation may have occurred during Norplant tre atment. Among cycles presumed to be ovulatory, the concentration of es trone glucuronide did not differ from concentrations during the contro l phase. However, mean (F=12.253, P=0.001) and peak (F=4.127, P=0.003) concentrations of pregnanediol glucuronide were significantly lower d uring Norplant treatment. Cycle duration did not differ during Norplan t treatment (F=1.415, P=0.200); however, duration of the total swellin g phase (F=3.311, P=0.011) and full swelling phase was shorter (F=5.90 6, P=0.011), whereas number of days with partial swelling increased (F =2.635, P=0.011). The results of this study indi cate that Norplant pr ovided effective contraception while not inhibiting ovarian hormone se cretion or the expression of cyclic genital swelling in the majority o f the chimpanzee subjects. (C) 1997 Wiley-Liss, Inc.