A JPMorgan analyst Thursday downgraded laboratory research products maker Invitrogen Corp., saying its shares were priced fairly and the company's restructuring plan would not pay off until 2008.

Analyst Tycho W. Peterson rated the stock at "Neutral," down from "Overweight." He said the Carlsbad, Calif., company is improving its operations, divesting its BioReliance subsidiary and combining other segments. However, he said it is risky to assume the stock will gain value in the short term.

"We believe the current restructuring will at least take the better part of this year, with benefits only beginning to be fully realized in 08," he said.

Although Peterson called Invitrogen's fourth quarter "modestly better than most had anticipated," he expects the company to post a bigger loss in the first quarter of 2007 than it did in the fourth quarter of 2007. He cut his earnings per share forecast for the year to $3.37 from $3.42.

Invitrogen shares closed at $66.99 Wednesday on the Nasdaq Stock Market. The stock has gained $10.40, or 18.4 percent, in 2007.