EFFECTS OF OLFACTORY-BULB ABLATION ON ESTRUS-INDUCTION AND FREQUENCY OF PREGNANCY

Surgical ablation of the olfactory bulbs was used to study the influence of olfaction on estrus induction in M. o. ochrogaster. Of 112 females pretested, 78% were induced to estrus. From a group of 56 operated females, 23 were completely bulbectomized (CB) and 33 were partially bulbectomized (PB) as determined from either microscopic or gross inspection. When housed cage-within-cage with males, CB females failed to become estrus. Similar tests using PB females results in 61% of these animals becoming estrus. When the females were housed in cages with males for one week, the frequency of pregnancy was 17% and 67% for the CB and PB females respectively. Thus, the response following partial bulbectomy was variable. The results show that complete bulbectomy blocked estrus induction and suggest that in this species male induced estrus is mediated via olfaction. © 1979.