Castration atrophy and pharmacological reactivity of the rat coagulating gland.

1. The reactivity and sensitivity of the rat coagulating gland to acetylcholine, adrenaline, serotonin and barium chloride was studied 7, 15 and 30 days after castration. 2. The wet and the dry weight of the coagulating gland progressively decreased with time after castration. 3. Spontaneous contractions were observed in the coagulating gland 15 and 30 days after castration. 4. The maximum force developed per gram tissue was significantly higher than control for serotonin and barium chloride on the 7th day, while for acetylcholine and adrenaline the increase was observed only on the 15th day after castration. 5. The pD2 values for adrenaline, barium chloride and serotonin increased significantly 15 days after castration, whereas the change in sensitivity to acetylcholine was detected only 30 days after castration. 6. These results suggest that changes in reactivity and sensitivity of the rat coagulating gland caused by castration are not related only to muscle atrophy, since the time course of the development of the effects is different for the four agonists studied.