Using gpg-agent like ssh-agent?

[Adam Funk]

I work with ssh-agent using ssh-add from the command line: "ssh-add
key0 key1 key2" to activate keys (sometimes with -t to set a time
limit), and "ssh-add -d key1" or "ssh-add -D" to deactivate them.

Is there a similar way to work with gpg-agent?