Citicorp, the nation's largest bank holding company, said yesterday that its first-quarter profit rose 24 percent over a year ago, while four other major bank holding companies also reported gains.

Security Pacific Corp., Bankers Trust New York Corp., Mellon Bank Corp. and Wells Fargo & Co. followed the growth trend of other banking companies this quarter, which has found most companies showing significant interest revenue increases.

Meanwhile, Eastern Airlines yesterday reported a $24.3 million first quarter profit, its largest in recent years, but the airline's glowing financial picture faded with its machinists union's unexpected rejection of a proposed contract.

Burroughs Corp. said its first-quarter profit rose 8 percent from a year ago, while another major computer maker, Honeywell Inc., said net income climbed 16.7 percent.

Citicorp reported a profit of $277 million ($2.02 a share) for the first three months of 1985, compared with $223 million ($1.64) a year earlier.

"The strong results reflect continued improvement of the world's economy and a somewhat lessening of interest rates here in the United States and in other important economies around the world," said Citicorp Chairman John Reed.

Net interest revenue rose 25 percent to $1.23 billion while revenue from fees and commissions was up 27 percent to $462 million, Citicorp said.

Citicorp is the holding company for the nation's second largest bank, Citibank. The banking company's total assets were $154.6 billion on March 31, compared with $141.8 billion a year ago.

Security Pacific, the nation's seventh-largest banking company, had an 8.2 percent rise in profit to $73.5 million ($1.00), compared with $67.9 million (92 cents) a year earlier.

New York-based Bankers Trust, the ninth-largest banking company, posted a 25 percent profit gain to $92.5 million ($2.74), compared with $74.1 million ($2.36) a year ago.

Mellon, which is based in Pittsburgh and is the nation's 11th-largest banking holding company, said its profit rose 25.8 percent to $41.5 million ($1.46) from $33.0 million ($1.20) a year earlier.

Wells Fargo, the 13th-largest bank holding company and parent to the nation's 10th-largest bank, said its first-quarter profit rose 12.2 percent to $44.95 million ($1.95) from $40.0 million ($1.52) a year ago.

The latest results include a $50.2 million pre-tax gain from the sale of the San Francisco-based company's residential mortgage banking unit.

The company said it also made a special addition of $65 million to its allowance for loan losses. The addition was a response to continuing international debt uncertainties, according to Chairman Carl E. Reichardt.

* Eastern Airlines Chairman Frank Borman attributed the results to "extremely strong first quarter traffic," the Pan American World Airways strike and cost control.

He said the profit would have been $53.2 million, but $28.9 million was put in reserve for the 1985 employe profit-sharing program.

"The strategy and plans have come to fruition at a successful airline," Borman said.

The profit was the third consecutive quarterly profit, and compared to a loss of $28.1 million in the first quarter of 1984. Eastern posted net profits of $3.6 million and $10.7 million for the third and fourth quarters of 1984.

Earning per share were 35 cents, compared with a loss of 97 cents in the quarter a year earlier.

In what was a surprise to both management and union leaders, the rank and file of the Machinists union Monday by a narrow margin rejected a contract proposal designed to help the carrier continue its financial recovery.

Borman said he believes the first quarter profit, with a healthy portion carved out for employes, will encourage union rank and file to reconsider the contract proposal. The tentative agreement had called for a lower pay scale for newly hired workers, but included 18 percent pay raises over three years.

Eastern said its operating profit for the quarter was $78.5 million, its highest ever, or $107.4 million before the reserve for profit sharing.

* Burroughs, which is based in Detroit, said net income increased to $46.6 million ($1.03) from $43 million (95 cents) a year earlier. The latest quarterly profit followed a charge of $3.1 million for the restructuring of certain operations, Burroughs said. Revenue rose 8 percent, to $1.17 billion from $1.08 billion.

* Honeywell, based in Minneapolis, said its first-quarter profit rose to $46.2 million ($1.00) from $39.6 million (84 cents) a year earlier. The year-ago results included a $5.4 million loss from discontinued operations.