What was going on when I was born?

-HOUR RIFFS On Fridays for the last 18 years, doctors, lawyers and business people have been escaping their professional worlds to participate in Jazz at Noon, a lunchtime jam session that now takes place at Freddy's, 308 East 49th Street, east of Second Avenue, from noon to 2:30. The performers, many of whom have played with name bands, always invite a guest star to join them. This afternoon, it will be the singer Maxine Sullivan. There's a $4 charge for listening. It's not necessary to buy food or drink, but Freddy's offers a $7.95 lunch with a choice of four entrees, and drinks start at $3. The number for more information is 888-1633. ELLY STONE'S NEW YORK

The Commerce Department ruled today that Brazil and Argentina have been subsidizing steel exports to the United States. This opens the way to duties that could cripple the nations' sales here and hurt their ability to meet interest payments on their large debts. But the department also announced that it had ended its investigation of related charges by the United States Steel Corporation that Mexico was subsidizing steel exports to the United States. Officials said the case was dropped after U.S. Steel informed the department it would withdraw its complaint because Mexico had voluntarily agreed to limit its steel exports.

The White House rejected Nicaragua's Deputy Foreign Minister as the next Ambassador to Washington at the insistence of the Central Intelligence Agency, Administration officials said today. They said the decision overruled a recommendation made by Secretary of State George P. Shultz and reflected the dominant role the C.I.A. has taken in determining United States policy toward Nicaragua. At the urging of the C.I.A., Administration officials said, the White House is also considering imposing economic sanctions against Nicaragua, including an embargo of banana imports and the cancellation of landing rights in the United States for Nicaragua's national airline, Aeronica. Those measures have been opposed by the State Department, the officials said. A final decision on the sanctions has not been made.

The economy grew at an annual rate of 8.3 percent in this year's first quarter, well above the 5 percent pace in the last quarter of 1983, the Commerce Department reported today. But economists, although surprised at the strength shown by the gross national product, attributed much of the rise to a sharp, unsustainable buildup of the inventories of goods that businesses keep in their factories and warehouses. For the current quarter, many analysts expect a sharp slowing in the growth rate of the G.N.P., which is the total value of all goods and services produced in the country. ''There is less there than meets the eye,'' Martin S. Feldstein, chairman of the Council of Economic Advisers, told reporters. Inventory accumulation accounted for half of the first quarter's increase, he said.

''There goes New Hampshire's ranking as the state with the lowest level of unemployment!'' - Mike Quimby, a carpenter laid off at the Seabrook nuclear plant. (A1:4.)

''AN AUSTRALIAN ACCENT'' at P. S. 1, 46-01 21st Street in Long Island City, is an exhibition with quite exceptional expressive power. The three artists involved, Mike Parr, Imants Tillers and Ken Unsworth, are image makers (and, sometimes, image scavengers) of a driving, obsessional and visionary sort. Their pictures come freighted with dreams, often of a complex and disquieting kind, and the idioms employed allow of a rapid and comprehensive attack upon a vast range of problems - emotional, conceptual, esthetic and perceptual. The images have also a bardic element, in that fundamentally these artists are tellers of tales and repositories of ancient wisdom. In particular, the Australian aborigine is much on their minds, as is indeed the case with every intelligent Australian. (Imants Tillers, the son of Latvians who went to Australia as displaced persons after World War II, has said that he ''would like to be accepted as a white aborigine.'')

It used to be, said Henry Maklakiewicz, a ramp service man, that when an Eastern Airlines ramp crew did not load a plane on time for its departure, no one ever asked why. ''They merely announced the delay,'' he said recently during a break from his job at Miami International Airport. But things have changed dramatically this year. Now when there is a delay, Mr. Maklakiewicz, as the lead ramp crew member, must not only find out why, but also report the reason to his supervisor. Mr. Maklakiewicz now also has the authority to clear a plane for takeoff once his crew has loaded it. In the past, only a supervisor could do that.

The Public Service Company of New Hampshire omitted dividends yesterday on both common and preferred stock for the first quarter. The utility, squeezed by ever-rising costs at the Seabrook nuclear power project, also ordered more layoffs and salary reductions, for a total saving of $38 million this year. The company's auditors said Public Service may be in default by next week unless it is able to secure additional credit. The company has a 35.5 percent share in the two Seabrook reactors, which are over budget by $6 billion to $8 billion, depending on the estimate used. Public Service is building the reactors as the head of a group of New England utilities.

An article in The Home Section yesterday on wheelchair maintenance gave an incorrect telephone number for the repair service of the Eastern Paralyzed Veterans Association in Fort Totten, Queens. The correct number is 352-1623.

THE city is chockablock with springlike things to do this Easter weekend, from ambling in the Easter Parade to greeting the new baby animals at the Bronx Zoo, from boarding the Cyclone roller coaster at Coney Island to oohing and ahing at the Mexican trapeze artists in the Big Apple Circus. The classic Easter Parade gathers momentum at around 11 A.M. It is highly unofficial, a decades-old annual gathering of well-dressed promenaders, who ply Fifth Avenue along the blocks north and south of St. Patrick's Cathedral. It began with the custom, years back, of elegant parishioners strolling along Fifth Avenue after attending Easter services at Manhattan churches. And the ''parade'' has been institutionalized by Irving Berlin's hit song, which has proved as durable, in its way, as the cathedral's lofty spires. Far uptown, in the bosky reaches of the Bronx, the zoo offers an efflorescence of infant fauna amid the spring flora. Dozens of new creatures are on display. The zoo's spring baby billing includes baby anaconda snakes, baby yaks and baby zebras. Some of the newcomers are in the two zoo nurseries, in the Reptile House and in the World of Birds building. Others hang out with their parents or their herds in outdoor environments.

A major portion of the Transit Authority's five- year, $6.5 billion capital program will be delayed because the agency cannot supervise the work adequately, according to the authority's president, David L. Gunn. Mr. Gunn, who took over the presidency two months ago, said he needed to postpone ''nonessential'' construction projects, such as a waiting area at a subway station, until the authority's management was reshaped, a process that he said might take a year. He said he was reviewing the capital plan and could not yet be specific about which projects would be delayed or for how long. But, he said, it is unlikely that any new construction of barns, shops and garages will be authorized before the fall.

J. David Dominelli has apparently fled the country, shortly before the currency trader was scheduled to appear at a contempt-of-court hearing on charges of not cooperating with the bankruptcy trustee overseeing the liquidation of his fallen financial empire. Mr. Dominelli, 43 years old, a former stockbroker who promised an estimated 1,500 people 40 percent returns on their investments in the fluctuating international currency market, faced a court hearing Friday. ''I'm sorry that the obstinate behavior and bullying tactics of the trustee and his attorneys and accountants have necessitated this action, but I see no alternative at this moment,'' Mr. Dominelli wrote in a letter to his associate and companion, Nancy Hoover.