NEW YORK (CNN/Money) - Shares of Apple Computer Corp. fell nearly 4 percent in early trade Thursday as the profitability of its newest line of desktop computers came into question.

Late Wednesday, Apple announced that it has raised the prices of its new iMac computers by $100 each. The company blamed an increase in component costs for the price hikes, which have been a rarity in the personal computer industry amid a protracted slump in demand.

With the increases, prices for a new iMac -- which comes complete with a flat-panel monitor -- now range between $1,400 and $1,900.

Specifically, Apple (AAPL: down $1.30 to $23.62, Research, Estimates) said the price increases were prompted by skyrocketing costs for flat-panel displays as well as the memory chips that are used in the iMacs.

"Since the new iMac's launch in January, memory costs have tripled and flat-panel costs have increased with little relief in sight," Phil Schiller, Apple's senior vice president of worldwide marketing said in a statement.

Even so, the company reported that demand for the new iMac's has been robust, saying it has shipped 125,000 of them so far.

But Apple's pricing move prompted some Wall Street analysts to lower their profit expectations for the company in the current quarter.

Prices for a new iMac now range between $1,400 and $1,900

"While it is a good thing that Apple is taking steps to protect its margins, we believe that Apple did this very reluctantly, as rising prices are a rarity in the PC industry," J.P. Morgan's Daniel Kunstler told his clients Thursday.

Kunstler trimmed his second-quarter earnings estimate for Apple to 6 cents per share from 11 cents per share, saying he believes "profitability on the new machines may have come close to evaporating in the quarter."

S.G. Cowen's Richard Chu also weighed in Thursday, telling his clients that although some of the impact of the higher component costs may be offset by tighter expense controls at Apple, he "wouldn't rule out" a possible 2-3 cents per share shortfall from his most recent estimate of 10 cents per share for the quarter.

By First Call's count, most analysts generally are expecting Apple to log a second quarter profit of 11 cents per share on roughly $1.4 billion in revenue.

Apple made the pricing announcement at its Macworld Tokyo exposition, where it also debuted several new products.

Among them were a 23-inch flat-panel display that will be available in April for $3,499; a larger-capacity, 10-gigabyte version of the iPod music player; a free, downloadable software program allowing iPod users to also store addresses and phone numbers in the device; and a free upgrade for the Apple OS X operating system to support Bluetooth, a short-range radio technology used to wirelessly connect various devices.