Showtime shifts 'Dexter' to summer

Showtime is splitting up its two most popular series.

Dexter and Homeland, which aired back to back in fall the past two years, will separate, so the network can use them as launching pads to introduce two new dramas.

Homeland, the Emmy-winning best drama, will remain in the fall, returning for a third season on Sept. 29. But Dexter, the serial-killer series starring Michael C. Hall, will air its eighth and probably final season starting June 30, its first summer run.

It will be followed by Ray Donovan, a new drama starring Liev Schreiber as a Los Angeles "fixer" to the rich and powerful. Jon Voight and Elliott Gould also star.

Homeland's new companion is Masters of Sex, a fictionalized biography of sex researchers William Masters and Virginia Johnson, that stars Michael Sheen and Lizzy Caplan.

Also due: The Borgias and Nurse Jackie return April 14, and The Big C will wrap up its run with four one-hour episodes beginning April 29, reflecting a "subtle change in tone," says entertainment chief David Nevins.

Nevins says the changes are an effort to capitalize on the channel's momentum. With 22 million subscribers, it is slowly gaining on HBO, with about 30 million, and is the "only premium channel to show consistent growth."