Retail gasoline supplies got still tighter yesterday with increasing numbers of service stations closed down either because their tanks were dry or to save gasoline for weekday commuters.

Unleaded gasoline, required for late-model cars with catalytic exhaust systems, was the first to run out in many areas.

While most District gas stations remained open, more than 70 percent of Virginia's gasoline stations were closed because of gasoline shortages, according to James Heizer of the Virginia Gasoline Retailers Association.

A spot check of suburban Maryland stations found that roughly 30 percent of the stations were open.

The fuel shortage results from recent tightening of supplies, due largely to the revolution in Iran, and to steadily increasing demand. Most major oil companies are limiting deliveries to a percentage of what each station sold last year, meaning that by month's end many stations are pumping from nearly dry tanks.

Heizer said Virginia's service stations should start receiving May gasolne allocations Tuesday, "But some deliveries won't be arriving until Wednesday or Thursday." He said early reports on gas allocations for May indicate that they may be five percent less than April's allotments.

An estimated 75 to 90 percent of stations in Connecticut, for example, were closed yesterday and many of the remainder were limiting their sales, Mike Klein, public relations director for the Hartford Automobile Club, told the Asociated Press.

Charles Matties, a member of the Connecticut Gasoline Retailers Association board of directors, blamed publicity in part for the shortage and for forcing stations to curtail operating hours.

"I would guess that this weekend we've got several hundred thousands of gallons of gasoline riding around in people's cars that they don't need. It feeds on itself." he said.

Similar pressures were evident in the Washington area.

Charlie Bridges, a mechanic at an Exxon station on Georgia Avenue just north of the Beltway, said his station was "pumping in six hours what we used to pump in 16. We can't keep open on Sunday because we wouldn't have any gas. We're only allowed 95 percent of what we pumped last year and we've already run out of extra and unleaded."

Bridges said consumers "don't seem to worry about a gas problem. In fact, they come in here and ignore the barricades, the signs, and they try to use pumps that are locked up. I have to fix a broken pump practically once a day."