Stock prices fell today, pressured by new evidence of sluggish business conditions. The Dow Jones average of 30 industrials dropped 23.02 to 2,897.77 by 2 p.m. on Wall Street. Losers outnumbered gainers by about 2 to 1 in nationwide trading of New York Stock Exchange-listed issues, with 472 up, 941 down and 518 unchanged. The Commerce Department reported that the gross national product grew at a 1.2 percent annual rate, after adjustment for inflation, in the second quarter of the year. The figure came in below most advance estimates. In addition, analysts noted that a significant amount of the increase stemmed from inventory expansion, a negative portent for production. Open-market interest rates declined in response to the news. For stock traders, however, the data seemed primarily to emphasize recent worries about the outlook for corporate profits. Many big-name stocks have run into selling of late on earnings reports that didn't live up to expectations. Walt Disney, for instance, dropped 4&lsqb; to 116~ after posting a 23.3 percent quarterly earnings gain that evidently disappointed some traders. Elsewhere, energy stocks were mostly higher on reports that the Organization of Petroleum Exporting Countries had agreed on a new oil production ceiling and reference price of $21 a barrel for the rest of the year. Exxon rose { to 49&rsqb;; Atlantic Richfield { to 124|; Amoco | to 54, and Texaco { to 62\. The NYSE's composite index of all its listed common stocks fell 1.46 to 193.09. At the American Stock Exchange, the market value index was down .79 at 355.54. Volume on the Big Board came to 105.17 million shares with two hours to go.