The Montgomery County Council has voted to protest a Department of Transportation proposal to look for alternatives to a planned Silver Spring-Glenmont subway route, and to hint that the county might withdraw funds from Metrorail if, as a result of the proposed study, an unsatisfactory alternative to the route is suggested.

The council agreed this week to put its protest in the form of a letter to Transportation Secretary Brock Adams. It will become the second such message to Adams from Montgomery County officials.

The impetus was a request from Adams last week that the Glenmont line be included in a year-old Department of Transportation restudy of Metro subway lines that are planned in addition to the 60 miles of lines that are already under construction or under contract. Purpose of the restudy is to determine whether other alternatives such as buses, trolleys or highways, could better serve the needs of the affected areas.

The 45 mile Glenmont line, expected to cost between $270 and $275 million, is the most expensive suburban segment, per mile, in the planned system. It is scheduled for completion in 1982. It was excluded from the federal study of alternatives, started last year, primarily because of pressure from Montgomery County Executive James P. Gleason. But now, Adams wants the line included in the study.

In a strongly worded letter last week, Gleason told Adams that unless the request for alternatives analysis is reconsidered, Gleason will reconsider the extent of his support for future construction and financial commitments for the Metro system.

Such action could include withholding future payments for construction of the Shady Grove storage yard, local sharing in interest payments on revenue bonds, rail operating subsidies, operation of stations serving predominantly federal installations, and any remaining obligations under the Capital contributions agreement of 1970, the letter said.

The letter to Adams that was approved this week by the council says that if a proposed alternative to the Glenmont line is not "demonstrably satisfactory . . . we will have serious questions about the validity of our financial and political commitment to the regional system.

"It may be, for example," the letter says, "that we and the state will decide that the needs of the Georgia Avenue corridor are of supervening priority requiring the withdrawal of funds now allocated to the Shady Grove segment of Metrorail."

Alexandria and Prince George's County have already taken positions against paying any of the Metro revenue bond interest, giving Montgomery County officials hope that Adams will bow to their pressure.

The motion to send the letter passed the Council 6-1, with member Jane Ann Moore voting against it.

Moore, an opponent of the Glenmont line, said she has "serious questions" about the line's costs and ridership. Citing decreasing population projections for the area, she said, "We may find this segment is not as cost effective as the alternatives."

Montgomery County officials reported these other developments:

The county Department of Health Systems Planning is seeking comments on proposed federal guidelines that will evolve into a national hearing planning policy. Comments from groups and individuals will be heard on June 27, at a meeting of the Health Services Planning Board at 611 Rockville Pike.

The county Fire and Rescue Services will conduct a cardiopulmonary resuscitation training course for the public on June 8, 15 and 22. Telephone 869-4191 for more information.

A public hearing on the county's application to the Department of Health, Education and Welfare for second-year funding and designation as a health systems agency will be held next Tuesday at the County Office Building.

A 24-hour telephone number has been installed to receive calls for an "abused persons" program. In addition to counseling, shelter will be arranged if needed. The program is designed to aid adults who are the victims of domestic abuse. The telephone number is 279-1331.