@entity284 blocks XXXX -mediated release of gonadotropins in @entity35 hypothalamus.

@entity18776 @entity251 @entity935 @entity1510 @entity284 @entity35 @entity7438
In the present study the effect of @entity284 (M) on gonadotropin-releasing hormone in the @entity35 hypothalamus was investigated. The specificity of the M effect was demonstrated by injecting M (100 ng) and the M antagonist, @entity1510 (5 ng), into the ventromedial hypothalamus. A significant drop in the blood @entity251 level (p less than 0.05) 15 min following M injection and reversal following @entity1510 administration suggest a decrease in synthesis or release of @entity7438 . To determine whether the @entity7438 response to @entity935 (DA) is altered by M, studies were conducted in vitro and in vivo. For the in vitro study hypothalami were incubated with M (10(-7) M), DA (10(-7) M), DA plus M, and DA plus M plus @entity1510 . Supernatants from the incubate were used to coincubate pituitaries in order to study the effect on luteinizing hormone release. Treatment of the hypothalamus with M had no effect on basal but inhibited the DA-stimulated release of @entity7438 . For the in vivo study @entity35 were pretreated with decarboxylase inhibitor ( @entity18776 ) followed by treatment per kilogram body weight with M (10 mg), L-dopa (1, 10, and 100 mg), L-dopa plus M, @entity7438 (500 ng), and M plus @entity7438 . M had no effect on the @entity7438 -induced increase in @entity251 levels, whereas the L-dopa-induced increase in @entity251 was blunted by M treatment. It is concluded that M blocks the DA-mediated release of gonadotropin-releasing hormone in the @entity35 hypothalamus.
