![]() |
|
|
RK Riemer, A Goldfien and JM Roberts
Department of Obstetrics-Gynecology and Reproductive Sciences, University of California, San Francisco 94143.
alpha 1-Adrenergic and muscarinic cholinergic stimuli activate uterine contraction. Estrogen increases adrenergic but not cholinergic sensitivity of rabbit myometrium independent of its effects on adrenoceptor concentration. Since both alpha 1-adrenergic and muscarinic receptors are coupled to phosphatidylinositol hydrolysis, we tested the hypothesis that estrogen increases adrenergic- but not cholinergic-mediated inositol triphosphate production. We found that maximal production of inositol phosphates stimulated by norepinephrine was increased approximately 3-fold following estrogen treatment. Cholinergic-stimulated production was not increased by estrogen treatment. These results demonstrate that the effect of estrogen to enhance uterine adrenergic sensitivity is associated with an increased post-receptor response. The nature of the selectivity of estrogen for adrenergic versus cholinergic response remains obscure, but the results suggest the presence of parallel pathways for receptor activation of a common post-receptor response.
This article has been cited by other articles:
![]() |
E Houdeau, A Levy, and S Mhaouty-Kodja Up-regulation of rat myometrial phospholipases C{beta}1 and C{beta}3 correlates with increased term sensitivity to carbachol and oxytocin J. Endocrinol., November 1, 2005; 187(2): 197 - 204. [Abstract] [Full Text] [PDF] |
||||