The first step in Lockheed Martin Corp.'s proposed merger with Comsat Corp. got the nod from federal regulators last week, sending Comsat's stock skyward.

Defense contracting giant Lockheed had offered to pay $45.50 a share for 49 percent of Comsat, the satellite company, as the first step in the merger of the two Bethesda firms. The purchase closed Saturday.

Uncertainty about how the Federal Communications Commission and the Justice Department viewed the merger had depressed Comsat's stock earlier this month. Early last week the price remained near its 52-week low of $27.37 1/2 set the previous week. But after the government approvals were announced on Wednesday and Thursday, the price jumped back up to close at $36 Friday, a 32 percent increase for the week.

Lockheed's stock was neither as volatile nor as blessed. On Thursday it fell to a 52-week low of $33.68 3/4. It closed Friday at $34.43 3/4, down 4 percent for the week.

The merger, however, is not complete. Lockheed plans to buy the remaining 51 percent of Comsat with its own stock, but it won't be able to do so without congressional action.

Like the broader stock market, the Washington Post-Bloomberg regional stock index had a rough week, dropping 2 percent to 168.01.

The local stock with the most dramatic drop was Dynex Capital Inc., a Glen Allen, Va., mortgage and consumer finance company. Dynex announced Friday that it will delay dividends on its series A, B and C preferred stock. It already has said it will not pay dividends on its common stock in the third quarter.

In a statement, the company said it was delaying the dividends because of recent downgrades in its debt ratings. Both Standard & Poor's and Fitch IBCA have lowered the company's credit rating in recent days. S&P said "the long-term possibilities for the company are limited," while Fitch said "default is a real possibility."

Dynex's stock fell $2.18 3/4 on Friday to close at $9.93 3/4, an 18 percent drop. The price fell 25 percent for the week.