Enhancement by L-Methionine on the Contractile Response of Uterine Segments to Acetylcholine and High KCI Is Mainly Due to Enhancement of Ca Uptake

Abstract

Acetylcholine (ACh)- and high KCI-stimulated ⁴⁵Ca uptake into rat uterine segments was inhibited by 3-deazaadenosine (3-DAA) plus homocysteine thiolactone (HCTL), and this inhibitory effect was attenuated by L-methionine (LMet). Ca-depleted Ringer solution in which uterine muscle had been incubated with L-Met did not enhance the contractile response of another uterine segment to ACh and high KCI in the presence of 3-DAA plus HCTL. These findings together with previous results suggest that the enhancing effect of L-Met on the contractile responses to ACh and high KCI is mainly due to an increase in Ca²⁺ uptake into the uterine muscle.