01643naa a2200241 a 450000100080000000500110000800800410001910000190006024500940007926000090017352009850018265000180116765000140118565000170119965000100121665000190122665000150124565000150126065000100127565000170128570000200130277300790132215228892023-11-13       1964    bl uuuu     u00u1 u    #d1 aLINDSAY, D. R.  aOestrogenic and anti-oestrogenic activity of androgens in the ewe.h[electronic resource]  c1964  aAbstract: Seventy-two spayed crossbred ewes were used in a series of five successive tests, at intervals of 15 days, in a study of the actions and interactions of androgen, oestrogen and progesterone on behavioural and vaginal oestrous responses. Androgen and oestrogen were additive in their action (128 vs. 62 services; P&lt0·001) on behavioural response, but androgen almost completely inhibited the expected vaginal response to oestrogen. There was a significant linear decline in behavioural sensitivity from test to test; in the five successive tests, forty-eight, forty-three, thirty-seven, thirty-two and thirty ewes were served (P&lt0·001). This refractory condition was partly offset by progesterone pretreatment (P&lt0·001), but oestrogen was necessary to maintain a constant state of psychic reactivity to androgen (P&lt0·001). A highly significant linear dose-response relationship was demonstrated with both testosterone and testosterone propionate (P&lt0·001).  aEndocrinology  aEstrogens  aReproduction  aSheep  aEndocrinologia  aEstrógeno  aFisiologia  aOvino  aReprodução1 aROBINSON, T. J.  tJournal of Reproduction and Fertilitygv. 7, n. 3, p. 267-274, Jun., 1964.