Profits at Washington Gas Light Co. increased in the 12 months ended Feb. 28 from $21.5 million ($3.69 a share) to $23.7 million ($3.73), company officials said yesterday.

Revenues for that period increased to $706.7 million from $609.5 million, and outstanding shares increased to 5,765,000 from 5,147,000.

BTR Realty Inc., a Baltimore company that owns and operates shopping centers, office buildings and other commercial properties, earned $923,672 (41 cents) during 1982, compared with $782,893 (35 cents) the year before. Revenues slipped to $12.3 million from $13.7 million.

Per-share earnings reflect two-for-one stock splits in 1981 and 1982.

Fourth-quarter profits were $222,913 (10 cents), compared with a loss of $11,702 in the final quarter of 1981. Revenues more than doubled to $4.7 million from $2.1 million.

The Washington Corp., another real estate company, posted 1982 profits of $1.2 million (45 cents), down sharply from earnings of $5 million ($2.14) in 1981. Revenues dropped to $3.3 million from $4.3 million in 1981.

In the fourth quarter, Washington Corp. earned $26,347 (1 cent), compared with profits of $3.9 million ($1.69) the previous year. Gross revenues declined to $428,932 from $3.2 million.