The Golden Ox Restaurant, long a fixture and a favorite near the corner of 16th and L streets NW in Washington's central business district, is going the way of the buffalo.

Local company officials, who asked not to be identified, confirmed that the restaurant will not relocate in Washington and is the victim of a corporate consolidation by its parent company, Kansas City Stock Yards of Maine Inc., located in Kansas City, Mo. "High rents," according to those officials, hobbled the Golden Ox. Company officials declined to say when the restaurant will close.

The block between 16th and 17th streets NW is being purchased by The Beacon Companies of Boston, which plans to construct a 13-story, 400,000-square-foot office building at 1615 L St. NW. The building, which is scheduled for completion in mid-1983, will have a "traditional exterior of glass and brick and will contain the most advanced energy conservation and life safety systems," according to Beacon vice president Alan Leventhal.

Inside, the building will have "a striking, eight-level, glass-walled atrium which will contain the elevator banks and retail facilities. It will also contain three levels of below-grade parking."

Architects for the project are Jung/Brannen and Associates Inc. of Boston and Vlastimil Koubek of Washington. The general contractor is Volpe Construction Co. of Boston, which has a major branch office here. Preliminary site work has already begun and full site excavation is planned for early 1982.

The Beacon Companies is an investment builder and owner-manager with a 35-year record of developing, building and managing diverse commercial and residential projects throughout the northeast.

The company maintains ownership interests in all its developments and has participated in many major urban developments, the most recent of which is One Post Office Square in Boston's financial district. This complex consists of a 41-story office building linked by a glass-walled atrium to the 328-room Hotel Meridien, which was created by the total renovation of the historic Federal Reserve Bank of Boston.

"We believe our building will be a positive addition to L Street and will be an architectural complement to its surroundings. There is a very real need in the District today for new, first-class office space downtown, and we are pleased to be able to participate in the major revitalization now under way in this great city," Leventhal said.

Several other small businesses along L Street NW sold their properties to Beacon and have closed or relocated. Capital City Furniture Co. recently moved to 1206 K St. NW, and Lynch Liquor has closed, but a sign in its window indicated it will relocate.

In other commercial real estate transactions:

* Arthur Rubloff & Co. has announced the following recent commercial leasing transactions in Montgomery County: Security Warehouse will lease 9,600 square feet of industrial space from Shady Grove Development Park; Audyxx Corp., a professional service firm offering in-house data processing facilities, has leased more than 6,000 square feet in Bethesda's Air Rights III Building on Wisconsin Avenue; Harleysville Mutual Insurance Co. has leased an office at 11600 Nebel Street in Rockville.

* The Washington Board of Realtors has leased 4,340 square feet in the Wyatt Building, 777 14th St. NW. The transaction was handled by the commercial leasing division of Shannon & Luchs.

* Automata Inc., manufacturers of printed circuit boards in Reston, broke ground for its new building earlier this month at 11091 Sunset Hills Road, Reston. The 55,000-square-foot structure, scheduled for occupancy by mid-1982, will be built by Beltway Construction Co. of Alexandria. Another Reston-based manufacturer, Datatronix, has begun construction of a 17,600-square-foot addition to its plant, located at 2100 Reston Ave.

* The Braedon Companies have announced plans to construct a 13-story, 185,000 square foot office building on 12 acres, christened Metro-Plex, adjacent to the New Carrollton Metro Station and the Amtrak Capital Beltway Terminal in Landover. The new facility will be the latest addition to the Metro East Office Park, which is planned to contain more than one million square feet of office and retail space. Metro-Plex, with floors averaging 14,500 square feet each, will include one floor of retail space.

Designed by Arthur Cotton Moore/Associates to "maximize window ratios as well as create efficient and flexible floor space," the building will be serviced by four high-speed elevators. Some floors have been designed to accomodate computer installations "more readily and cost-effectively." The tenth floor alone will have balcony areas, overlooking "sensational landscaping" that will "provide a highly desirable work environment both inside and out."

The entire structure will be serviced by "state-of-the-art" computerized environmental control systems, according to Braedon Companies' slick brochure. Landmark Associates, a national real estate development company headquartered in Philadelphia, and active in several states, is the developer of Metro-Plex.