PT  - JOURNAL ARTICLE
AU  - R K Riemer
AU  - A Goldfien
AU  - J M Roberts
TI  - Estrogen increases adrenergic- but not cholinergic-mediated production of inositol phosphates in rabbit uterus.
DP  - 1987 Nov 01
TA  - Molecular Pharmacology
PG  - 663--668
VI  - 32
IP  - 5
4099  - http://molpharm.aspetjournals.org/content/32/5/663.short
4100  - http://molpharm.aspetjournals.org/content/32/5/663.full
SO  - Mol Pharmacol1987 Nov 01; 32
AB  - 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.