The present invention addresses the problem of providing a medicinal composition and in particular a compound suitable for treating nocturia. Under the expectation that nocturnal urinary frequency could be reduced via an antidiuretic action said antidiuretic action being induced by inhibiting placental leucine aminopeptidase (P LAP) that is an AVP metabolic enzyme at night and thus maintaining and/or increasing endogenous AVP concentration extensive studies were made on compounds capable of inhibiting P LAP. As a result it was discovered that a (2R) 3 amino 2 [(4 substituted pyridin 2 yl)methyl] 2 hydroxypropanoic acid derivative has an excellent P LAP inhibiting effect. By testing the antidiuretic action using drinking water loaded rats furthermore it was discovered that the aforesaid compound has an effect of suppressing urine production due to an increase in endogenous AVP concentration based on the inhibition of P LAP. Thus the present invention provides a compound that is likely usable as a therapeutic agent for nocturia based on a mechanism of inhibiting P LAP.
