How to get values from a "cell" of a "groupby" object?

Assume that I have the following data frame:

     A    B  C   D
0  foo  one  1  10
1  bar  one  2  20
2  foo  two  3  30
3  bar  one  4  40
4  foo  two  5  50
5  bar  two  6  60
6  foo  one  7  70
7  foo  two  8  80

Now I can group by the first column: grouped = df.groupby('A'). As a result I get the following DataFrameGroupBy object:

     A            B                 C              D
0  foo  [one,two,two,one,two]  [1,3,5,7,8]  [10,30,50,70,80]
1  bar  [one,one,two]          [2,4,6]      [20,40,60]

Now I would like to access the values from a particular cell. How can I do it? For example I want to get the values from the column 'D' and the row where 'A'=='foo' (the first row). In other words I want to get [10,30,50,70,80]. Is it possible?