Viacom Inc.’s first-quarter net income declined 9 percent to $317.2 million as higher interest expenses overcame gains from film studio DreamWorks SKG, which the company acquired last year.

The contribution by DreamWorks, along with 7 percent growth at the MTV-led cable television unit, helped drive revenue up 12 percent to $2.4 billion. That was offset by $56.8 million in interest rate expenses, weaker revenue overseas and $9.4 million in stock option expenses. Viacom’ s profit for the quarter was 43 cents a share compared with 47 cents a year ago, when net income was $350.3 million.

Viacom, created when Chairman Sumner Redstone split the old Viacom’s faster-growing assets from slower-growing businesses, beat some analysts’ estimates in its first quarterly financial report. Without the contribution from the DreamWorks unit, acquired in the fourth quarter last year, the new Viacom would have met estimates. That may dampen Mr. Redstone’s argument that the split in itself will “unlock value” from the old Viacom’s assets.

“Viacom’s consolidated results were somewhat better than we anticipated, but the difference appears to have been driven entirely by the DreamWorks acquisition,” Merrill Lynch analyst Jessica Reif Cohen said in a report Thursday.

Redstone pitched the new Viacom as a growth company fueled by assets such as MTV and Paramount Pictures. CBS Corp., which reported its quarterly results for the first time as an independent company earlier this month, was fashioned as the value company, with businesses such as the CBS network, radio and billboards generating lots of cash and less growth.

The new Viacom’s cable-TV operation boosted its sales 7 percent to $1.6 billion. Growth in advertising revenue and payments from cable and satellite companies was tempered by a 13 percent decline in overseas advertising revenue, mainly in Germany. Operating income at the cable segment climbed 8 percent to $621.1 million.

The film division posted a revenue increase of 25 percent to $824.9 million, fueled largely by DreamWorks, which added $174.1 million to the revenue figure. The unit also got help from robust home-video sales and television license fee revenue. However, operating income for the division fell 28 percent to $51.1 million due to higher expenses tied to film releases.