adressing column

i have the following function:

declare
  prim_col_name Alias for $1;
  prim_col_val Alias for $2;
  my_column Alias for $3;
  link_table Alias for $4;
  link_col Alias for $5;
  data_table alias for $6;
  my_record Record;
  result_string varchar;
  i integer;
begin
  result_string := '';
  i := 0;
  For my_record in execute 'select ' || my_column || ' from ' ||
data_table || ' where ' || link_col || ' in (select ' || link_col || '
from ' || link_table || ' where ' || prim_col_name || ' = ' ||
prim_col_val || ') order by lower(' || my_column || ')' loop
      if i = 0 then
         result_string := my_record.col;
      else
         result_string := result_string || ', ' || my_record.col;
      end if;
      i := i + 1;
  end loop;
  return result_string;
end


now i am searching for a way, to access my_column in my_record (now it
just works if  my_column = 'col')
can anyone help please!
thanx
steffn