An organosilicon compound, 2,615s -diphenylhexamethylcyclotetrasiloxane, was investigated as an orally active estrogenic antigonadotropin in the male rat and compared to subcutaneously administered estradiol benzoate. The cyclosiloxane lowered serum LH and FSH in association with sex accessory tissue atrophy. Serum LH declined to 50 % of the control level within 5 hrs. of a single dose of the cyclosiloxane; FSH declined more slowly. Gonadotropin levels were further decreased to 15-20 % of the control level after one week of treatment. A direct anterior pituitary block was demonstrated in LFW challenged animals 8 hrs. after a single dose of the cyclosiloxane; estradiol blocked the pituitary as early as 1 hr. after estrogen administration. The cyclosiloxane decreased available releasing hormone activity at 24 hrs. This action was associated with an increase in the median eminence content of dopamine and an in vivo decrease in the rate of synthesis of dopamine from 14C-tyrosine. Estradiol had a similar but weaker effect. On the basis of these data it was postulated that this unusual nonsteroid structure exerts its effects at the level of the anterior pituitary and on the hypothalamus.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.