MTV series guru Lois Curren will "scale back responsibilities," according to the network, just months after being promoted to president of entertainment and programming at the network.

"Lois has decided to scale back responsibilities for personal reasons, transferring key administrative duties while continuing to focus on a wide variety of creative projects including series like 'Room 401,' the untitled Menudo project and 'The Kentucky Kid' and the roster of pilots already in development," an MTV spokeswoman said.

Sources said Tony DiSanto, executive vp series development and animation and head of programming at MTV2, will step in to assume day-to-day responsibilities for ongoing development.

Sources indicated earlier that Curren had resigned from her post, but she will retain her title.

With Curren's absence, MTV loses a longtime key player in its bustling programming division. Curren reported to Brian Graden, president of entertainment at MTV Networks Music Group and Logo. The execs formed a tightly knit team for the past decade at the network.

In February, Curren was promoted from executive VP series entertainment. She oversees development, program planning, production and scheduling at MTV. MTV gave no indication of Curren's status at its West Coast upfront presentation Thursday.

MTV has been fighting furiously to keep its competitive edge in primetime television, not to mention the pop culture world at large. The network averaged 522,000 viewers in the 12-24 demo during primetime in the first quarter, down 5% from the previous year, according to Nielsen Media Research.

Ratings also have been in decline in the 10 Spot, MTV's showcase for original series, averaging 454,000 viewers in the 12-34 demo during the first quarter -- nearly half of what they were in MTV's prime in 2004, when "Osbournes" and "Newlyweds" reigned. Erosion has been most noticeable in some of MTV's longest-running franchises, including "TRL" and "The Real World."

In its most recent slate announcement in February, MTV signaled it was going to explore more scripted series programming given the glut of reality shows from competing networks. Proposed programs included "Kaya," a single-camera half-hour scripted series about a musically gift young woman who becomes an overnight sensation.

The network also is aggressively pursuing a multiplatform strategy that will increasingly rely on user-generated content. In January 2006, MTV restructured its creative management ranks and expanded Curren's oversight from strictly West Coast TV development to all longform programming efforts at the channel, while moving most of the rest under Dave Sirulnick, executive vp multiplatform production, news and music.

Curren caps a flurry of activity from some of the top female TV execs in the business. This week, Lifetime Entertainment Services CEO Betty Cohen resigned from the top job and was replaced by Andrea Wong, executive vp alternative programming, specials and late-night at ABC Entertainment. Last week, Fox TV Studios chief Angela Shapiro decamped for the top job at cable network TLC.

Curren joined MTV in 1998 as senior vp music development. She played an instrumental role in transforming MTV from a repository of music videos to a hit-series machine. Before joining MTV, Curren developed programming at Columbia TriStar Television Distribution. She also served with Graden at the now-defunct Foxlab, an alternative-programming production company under 20th Century Fox that developed series including "Studs."

Kimberly Nordyke contributed to this story.