UPDATE 2-Health Net results top forecasts, shares rise

* Third-quarter adjusted profit beats forecasts by 6 cents

* Revenue rises 3.9 percent to $4 billion

* Plan enrollment falls 3.8 percent from a year ago

* Trims high end of full-year earnings estimate range

* Shares rise 4.07 percent to $15.85 on NYSE (Adds earnings details, analyst comments, share activity)

CHICAGO, Nov 3 (Reuters) - Regional health insurer Health Net Inc (HNT.N) reported adjusted quarterly earnings on Tuesday that beat expectations, helped by strong sales in the western United States and lower administrative costs.

The Los Angeles-based company reported a third-quarter net loss of $66 million, or 64 cents a share, compared with net income of $18.5 million, or 17 cents a share, a year earlier, largely due to charges related to the pending sale of its Northeast division to UnitedHealth Group Inc (UNH.N).

Excluding special items, Health Net reported earnings of $69.6 million, or 67 cents a share.

Analysts on average had expected earnings excluding items of 61 cents a share, according to Thomson Reuters I/B/E/S.

Third-quarter revenue rose 3.9 percent to about $4 billion, helped by an increase in health plan services premium revenue, as well as higher revenue from government contracts.

Health Net spent 87 percent of its commercial premium revenue on medical costs, compared with 86.7 percent in the third quarter a year ago.

Total health plan enrollment fell 3.8 percent from a year ago to about 3.6 million members.

"Results look consistent with the sector themes this quarter, with pressure from commercial medical cost trend (and) lower commercial enrollment offset by generally stronger results from government programs," Goldman Sachs analyst Matthew Borsch said in a note to clients.

Health Net narrowed its forecast range for full-year earnings excluding special items to $2.25 a share to $2.30 a share, taking 5 cents off the top end of its previously forecast range.

Health Net shares were up 62 cents, or 4.07 percent, at $15.85 at midday on the New York Stock Exchange. (Reporting by Susan Kelly; editing by Andre Grenon)