Manor Care Inc. of Silver Spring said yesterday its first-quarter earnings rose 29 percent, primarily as a result of the improved performance of its nursing homes.

The company recorded a profit of $8.5 million (22 cents a share), compared with $6.6 million (17 cents) in the first quarter of fiscal 1989. Sales in the quarter also were up, rising 13 percent to $194.7 million from $173 million.

Manor Care operates 163 nursing homes and a motel- and hotel-franchising division called Choice Hotels International that manages 2,301 properties under such names as Clarion, Comfort Inn, Quality Inn, Rodeway Inn and Econo Lodge.

Operating profits increased in the nursing-home division, according to the company, because of declining costs and higher occupancies at the 35 facilities it has opened since 1987 and because of stable margins and increased rates at its older institutions. About 80 percent of Manor Care's profits and sales come from its nursing homes.

The company said its acquisition of the Econo Lodge, Friendship Inn and Rodeway Inn franchise systems this summer will add about $35 million in sales to the lodging group, but would contribute little to the company's bottom line this year because of operating costs.

Penril Corp., a Gaithersburg-based company that makes data communications products, said its profits rose 29 percent in the fiscal year ended July 31 and 25 percent in the fourth quarter.

In the year, Penril earned $5.4 million ($1.11), compared with profits of $4.2 million (90 cents) a year earlier. Revenue gained more than 10 percent, to $46.6 million from $42.2 million.

In the quarter, Penril said it earned $2 million (40 cents), compared with $1.6 million (34 cents) in the year-ago quarter. Revenue rose 13 percent, to $13.7 million from $12.1 million.