STIMULUS CHARACTERIZATION OF ESTRADIOL APPLYING A CROSS-FAMILIARIZATION TASTE-AVERSION PROCEDURE IN FEMALE MICE

In female mice (n = 240), the estradiol stimulus was characterized by studying preexposure effects of sex steroids and sickness-inducing dru gs on estradiol-induced (50 mug/kg SC) conditioned taste aversion (CTA ). It was established that preexposure to estradiol itself (2-50 mug/k g SC) attenuates the development of CTA produced by the hormone. Only partial crossfamiliarization effects were found with progesterone (50- 200 mug/kg SC) and testosterone (250-1000 mug/kg SC), steroids that in duce CTA themselves. Preexposure to the sickness-inducing drugs lithiu m chloride (22 mg/kg SC) and apomorphine (0.1-0.2 mg/kg SC) prevented or substantially reduced the development of estradiol-induced CTA, res pectively. It was concluded that only a low degree of stimulus resembl ance exists between estradiol and the other principal sex steroids, pr ogesterone and testosterone. In addition, it was concluded that the es tradiol stimulus resembles the stimuli produced by sickness-inducing d rugs.