U.S. Steel Corp., feeling the effects of the drop in oil prices, recorded a $249 million first-quarter loss, but officials are "cautiously optimistic," Chairman David Roderick said yesterday.

Another member of the steel industry, National Steel Corp., reported a first-quarter net loss of $39.4 million, little changed from a $39.8 million loss in 1985.

And problems in the oil industry gave Southland Corp. a first-quarter loss.

The U.S. Steel loss, which amounted to a drop of $1.06 a common share, compared with a profit of $185 million (63 cents) on sales of $5 billion in the first quarter of 1985. The company had sales of $4.7 billion in first-quarter 1986.

U.S. Steel owns Marathon Oil Co. which, merged with Texas Oil & Gas Corp. in February.

Since the beginning of the year, the company has reduced its work force by about 1,000 people, Roderick said, and more layoffs could follow.

*National Steel Corp. sales for the first three months of 1986 were $472.5 million, down from $514 million a year earlier, the company said.

National Steel, the nation's sixth-largest steel maker, said quarterly shipments declined 5.4 percent to slightly more than 1 million tons, down from 1.12 million tons in the first three months of 1985.

The company is owned equally by National Intergroup Inc. of Pittsburgh and Nippon Kokan K. K. of Japan. National Intergroup has said it wants to sell its 50 percent interest in the joint venture.

*Southland Corp., of Dallas, lost $88.5 million because of the effects of the oil price drop on its Citgo Petroleum Corp. subsidiary, company officials said yesterday.

Southland, which owns 8,271 7-Eleven convenience stores, said Citgo's loss was tempered by the best first quarter in 7-Eleven's history, as sales growth was 5.9 percent above inflation for those stores open more than a year.

The loss, on revenue of $3.07 billion, compared with a profit of $1 million (2 cents a share) on revenue of $2.81 billion in first-quarter 1985.