GASTRIC-MOTILITY IN RATS WITH VARYING OVARIAN HORMONE STATUS

Gastrointestinal (GI) symptoms suggestive of altered motility vary wit h menstural cycle phase and menopause, but the effects of ovarian horm ones on gastric motility have not been described. Basal and stimulated gastric motility were studied in male and female rats that were ovari ectomized and implanted with continuous-release progesterone and/or es trogen pellets. Following 26 days of hormone treatment, rats were impl anted with a gastric tension transducer. Contractile activity was reco rded, then thyrotropin-releasing hormone (TRH) or saline was injected intracisternally and motility was monitored. An index was calculated b ased on frequency and amplitude; response to TRH was expressed as perc entage of the basal index. Basal contraction frequency was highest in the estrogen and estrogen + progesterone groups. Hormone treatment sig nificantly affected the TRH-stimulated motility index; TRH induced inc reased motility in all groups, with larger, more sustained responses i n vehicle, progesterone, and male groups. Results demonstrate the ovar ian hormone modulation of basal and stimulated gastric motility. Such modulation may contribute to changes in GI symptoms with altering ovar ian hormone state.