  We have performed a photoemission study of La$_{1-x}$Sr$_x$TiO$_{3+y/2}$ near
the filling-control metal-insulator transition (MIT) as a function of hole
doping. Mass renormalization deduced from the spectral weight and the width of
the quasi-particle band around the chemical potential $\mu$ is compared with
that deduced from the electronic specific heat. The result implies that, near
the MIT, band narrowing occurs strongly in the vicinity of $\mu$. Spectral
weight transfer occurs from the coherent to the incoherent parts upon
antiferromagnetic ordering, which we associate with the partial gap opening at
$\mu$.
