FIGURE 2.

Examples of levels of circulating prolactin and LH in whole blood samples collected by the tail tip method in individual C57BL/6J and Swiss Webster mice during diestrus and proestrus of the reproductive cycle. Repeated tail blood sampling in individual C57BL/6J (A–F) and Swiss Webster (G–L) mice during either diestrus or proestrus in a single cycle. (M–O) Prolactin and LH secretion profiles from single C57BL/6J mice in which blood samples were collected over two consecutive days of a single estrous cycle. Red arrow indicates maximum LH levels recorded during proestrus