"MCI -- That stands for Money Coming In," MCI Communications Corp. Chairman William G. McGowan told MCI shareholders two years ago, just as the company's earnings finally started to take off after years of little growth.

Today, in spite of a recession, a costly acquisition of an international telecommunications company, increasing competition from new long-distance firms and sharply higher operating costs, money still is pouring into MCI -- although perhaps not at as rapidly as McGowan or many financial analysts had hoped.

Yesterday the company announced earnings of $37.6 million (39 cents a share) for its second quarter ended Sept. 30 -- more than double last year's $15.4 million (15 cents) in profits for the same quarter. Revenues totaled $261.7 million, up 128 percent from last year's total of $115 million.

First-half profits soared to $74.06 million (76 cents) from $26.11 million (25 cents) as revenues increased to $96.87 million from $87.02 million.

Although a sharp jump over the last fiscal year's second-quarter profits, earnings represented only a modest gain over MCI's previous quarter when profits totaled $36.5 million (36.5 cents).

According to McGowan, the reasons were threefold: a recessionary economy where many consumers cut back on long-distance calls this summer, the costs of incorporating its $134 million acquisition of Western Union International, and the large expenses the company incurred in its efforts to enter the brand new mobile telephone market.

As ever, McGowan is optimistic that the company's financial growth will pick up in the remainder of the year -- so much so that he is sticking to his prediction that the company's revenues will total more than $1 billion for this fiscal year -- more than double last year's sales.

Nonetheless, McGowan acknowledged in an interview this week that the company cannot sustain a 100 percent growth rate forever. "Next year it will be practically impossible to gain 100 percent on top of what we did this year. But I'm certainly going to give it a try," he said.

To make that effort, however, MCI plans to enter a variety of new telecommunications markets aggressively, relying primarily on heavy promotional campaigns much like the ones MCI used to launch its residential long-distance service two years ago

In a New York meeting with financial analysts today, McGowan plans to unveil the company's ambitious advertising campaign promoting "intelligent" pagers. MCI entered the paging industry three months ago when it acquired Western Union International and its subsidiary, Air Signal.

Beginning shortly in Dallas and then in other cities, MCI plans to market a pager that will let the consumer know who is trying to reach him and why -- all through a digital readout. McGowan said he hopes eventually to sell pagers cheaply enough that they will become a popular consumer good for everyone, not just doctors, business people and "effete snobs. We're going to change the image" of people who use pagers, McGowan said.

Additionally, by the end of the year, McGowan hopes to have signed agreements with at least two foreign governments that will permit the company to offer some international telephone service in competition with AT&T, which has had a monopoly in routing international calls.

At the start of 1983, MCI also hopes to add to its voice network a network to allow the high-speed transmission of data. The company plans to begin upgrading its microwave system within the next few weeks to begin handling the digital transmission.

These plans come on top of the company's aggressive push to enter the new mobile telephone service, cellular radio, that scores of other companies also are pursuing eagerly. MCI already has spent $3 million in legal and engineering fees in its efforts to seek government permission to operate the system. MCI already has applied for government licenses in 12 cities and plans to file for 30 more soon.

Despite McGowan's bullish plans, many Wall Street analysts who have been equally enthusiastic about the company are now having their doubts--especially as the stock, which split 2 for 1 in September, climbs high into the $20-a-share range.

"I think the stock is a little rich now," commented Harry Edelson of First Boston, shortly before MCI shares jumped 2 3/4 to 27 3/8 on Wednesday, when 2.7 million shares were traded. The stock closed yesterday at 27 1/2, before the earnings were announced.

Edelson and a number of other analysts are concerned that the going will get tougher for MCI now, especially as the divestiture of American Telephone & Telegraph Co. approaches. "The risk of added competition, which has been more or less on the sidelines, is going to increase," he said.

Add to that the concern over the economy, fears that MCI will have to pay ever higher fees to gain access to local telephone networks, and signs that MCI will have to cut prices sharply in the international telex market to keep up with increasing competition, and several analysts are becoming more cautious about the aggressive, 14-year-old company.

Yet others, while acknowledging MCI's earnings are lower than they had hoped for, still are banking on the Washington-based company's long-term growth. "I'm probably more excited about the company than I have been in the last year," says Steven G. Chrust of Sanford C. Bernstein, who has been one of Wall Street's most bullish advocates of MCI.

One reason for Chrust's optimism: MCI is trying to pick up the revenue it is losing from the recession by offering a new telephone service, Omni call, that allows customers to call anywhere in the United States -- not just where MCI has its microwave facilities. MCI can offer this service by leasing discount long-distance telephone lines from AT&T, then passing on some of its discount to consumers.

As a result of Omni call, McGowan says the company has experienced a 47 percent increase in traffic from existing customers.