SEXUAL STEROID PROFILES AND OVARIAN ACTIV ITIES OF THE FEMALE PANDA YAN-YAN IN THE ZOO OF BERLIN

The nine years old giant panda YAN YAN was received in April 1995 on l oan for 5 years to the Berlin Zoo. Urine samples were collected daily or every second day from April 1995 to June 1996 in order to follow up sexhormone secretions and ovarian activities. Conjugated steroids wer e hydrolysed, extracted and measured with two enzyme immune assays (EI A) being specific for either total oestrogenes or pregnandiol. The eva luation of the hormone secretion pattern yielded the following results :There is a significant synchronous cross correlation between estrogen and progestin metabolites secretion indicating its simultaneous synth esis. In addition, we found a regular increase and decrease of both ho rmones with a 13 days interval. This secretory pattern indicates repea ting development and atresia of follicle cohorts with a cycle length o f about 13 days. Only a single period of sligthly elevated oestrogen s ynthesis was monitored in Feb. 96 without any signs of oestrus. Obviou sly the stimulation of ovarian function was insufficient for complete ovulation and corpus luteum formation.