2. Morphometric analysis of immuno-labeled hypothalamic neurons
The large number of the immersion-fixed tissue specimens enables the morphometric studies of neurons to establish sex differences and aging-related changes. The example in the figure reveals a significant sex difference in the size (mean profile area) of human kisspeptin neurons in the infundibular nucleus of middle-aged male and female humans. The increased cell size in postmenopausal women is a consequence of a neuronal hypertrophy in the absence of estrogens (for details, see Hrabovszky et al., Front Endocrinol (Lausanne): 2:80).