Latex Beamer: Itemize first level bold

Question

does anybody know how to print the first level of an itemize environment bold? I tried \setbeamertemplate{itemize/enumerate body begin}{\bf}, but then also the subitems are printed boldface... Here is my MWE:

\documentclass[t,8pt]{beamer}

\begin{document}

\begin{frame}{Insert page title}{Subtitle}
  \begin{itemize}
    \item First level
    \begin{itemize}
        \item Second level
        \begin{itemize}
            \item Third level
        \end{itemize}
    \end{itemize}
    \item Again first level
\end{itemize}
\end{frame}

\end{document}

I would like it to look like this:

Thank you very much in advance!

Answer 1

DO NOT USE \bf IN MODERN LaTeX DOCUMENTS!

\documentclass[t,8pt]{beamer}

\setbeamerfont{itemize/enumerate body}{series=\bfseries}
\setbeamerfont{itemize/enumerate subbody}{series=\normalfont}

\begin{document}

\begin{frame}{Insert page title}{Subtitle}
  \begin{itemize}
    \item First level
    \begin{itemize}
        \item Second level
        \begin{itemize}
            \item Third level
        \end{itemize}
    \end{itemize}
    \item Again first level
\end{itemize}
\end{frame}

\end{document}