* U.S. shale output up but expected to slow in the coming years
* Poll finds U.S. crude stocks fall for third straight week
* OPEC cutting production to rein in oversupply
* China, Japan indicate stimulus measures to boost growth (Changes dateline to New York, add latest prices, quote)
NEW YORK, Jan 23 (Reuters) - Oil prices turned negative on Wednesday, following U.S. stock markets down, on concerns about global economic weakness, forecasts for record U.S. shale production and lower U.S. gasoline prices.
Brent futures were down $1.07, or 1.7 percent, at $60.43 a barrel by 11:58 a.m. EST (1658 GMT), while U.S. West Texas Intermediate crude fell 99 cents, or 1.9 percent, to $52.02 per barrel.
"Today's trade is extending a daily pattern of oil moving in close tandem with swings in the equities," Jim Ritterbusch, president of Ritterbusch and Associates in Chicago, said in a report.
The Dow Jones Industrial Average turned negative around midday Wednesday after rising about 1.2 percent earlier in the day.
Ritterbusch said he expects "the energy complex will prove more reactive to large equity sell-offs than to rallies as this month proceeds."
(Additional reporting by Noah Browning in London and Henning Gloystein in Singapore; Editing by Marguerita Choy and Alexandra Hudson)