American Security Bank, in a move to bolster its business lending, last week named King F. Lowe its new executive vice president in charge of lending activities.

Lowe, formerly executive vice president for U.S. banking with the European American Bank, will head American Security's wholesale banking group. The new post will include responsibility for international, national and local business banking, corporate finance and real estate. Real estate loans and energy-related loans have been a major source of problems at American Security in recent years.

The bank, Washington's second-largest, reported a loss of $11.9 million for the fourth quarter of 1984 after having to deduct $37 million from its earnings to cover possible loan losses. At the time, the bank reported it had promised the Comptroller of the Currency that it would take steps, including a review of personnel, to strengthen its lending position.

Lowe's appointment also follows the succession two months ago of Daniel J. Callahan III to the position of chairman and chief executive officer. Callahan replaced W. Jarvis Moody, who resigned for health reasons. In his new position, Lowe will report directly to Callahan.

A graduate of Harvard University's undergraduate and advanced management programs, Lowe has served for the last 12 years with the European American Bank in New York, initially as senior vice president. Before that, he was with Chase Manhattan Bank.

In a related announcement, American Security promoted two vice presidents, Richard P. Roulier and Alicia R. Castaneda, to senior vice presidents.

Roulier, who joined American Security from rival Riggs National Bank in 1981, will head the metropolitan banking division, which is responsible for the bank's commercial relationships in the District, Maryland and Northern Virginia. A graduate of Columbia University School of International Affairs and New York University Law School, Roulier also has worked at Citibank's international division.

Castaneda was named senior vice president of the bank's treasury division for both international and domestic funding. A graduate of the University of Valle, Colombia, she joined American Security's international division in 1976.