The Bethesda Business Center and Law Offices, a "shared-office" facility in the Bethesda Metro Center that houses 90 furnished offices, opened last week.

The center features four conference rooms, a word-processing center and other communications areas, a reception area and a law library on the seventh floor of the new office building in Bethesda.

Clients at the center rent one or more offices at prices ranging from $500 to $1,200 a month and use the facility's services, including secretaries, as needed.

Interoffice, which manages the facility, operates four other shared-office facilities in Washington and Baltimore. According to the firm's president, Paul Swindley, the complexes are designed to avoid the expense and "hassle" of setting up an office.

Other recent developments in commercial realty in the Washington metropolitan area:

*Executive Quarters Inc. recently announced the opening of a new shared-office facility on the ninth floor of the Securities and Exchange Commission/Judiciary Plaza building at 450 5th St. NW. The new office plans to cater to companies, such as law firms and brokerage houses, that require an office near the SEC.

*Sperry Corp. has signed a lease for about 18,000 square feet at 8500 Leesburg Pike in Vienna to use as a sales and marketing office.

*Lotuse Development Corp., a computer software firm, has signed a lease for about 6,000 square feet at 1100 Wilson Blvd. in Arlington.

*CACI Inc.'s federal division has signed a $1 million lease for 9,900 square feet at 1725 Jefferson Davis Hwy. in Arlington.

*CACI Inc. has leased 19,000 square feet for $2.1 million at Rosslyn Center in Arlington.

*System Development Corp., a computer software firm, has leased 13,180 square feet at 8229 Boone Blvd. in Vienna from GTE Telenet.

*Washington Federal Savings & Loan has signed a $2.2 million lease for 21,800 square feet at 516 Herndon Pkwy. in Herndon from Van Buren Ltd.

*Christian Broadcasting Network, a television network, has leased 3,530 square feet at Fair Oaks in Fairfax from Rouse & Associates.

*Sancor Ltd., an investment company, has signed a lease for 1,832 square feet at 8201 Greensboro Drive in McLean.

*Professional Personnel, an employment agency, has leased 3,945 square feet at 8201 Greensboro Drive in McLean.

*The Circle Inc., a medical consulting firm, has signed a $2.1 million lease for 10,000 square feet at 8201 Greensboro Drive.