Histomorphometric analysis in the ovary of newly hatched chicks treated with follicle-stimulating hormone during embryonic development

We studied the histomorphometric changes induced in the left ovary of newly hatched chicks treated with follicle stimulating hormone (FSH) during embryonic development. After FSH treatment the thickness of the ovarian cortex, the number per unit of area and total mass per ovary of germ and pregranulosa cells increased, accompanied by hypertrophy of the pregranulosa cells. The volume of interstitial cells cords, lacunar system, and blood capillaries was increased and modifications in poorly differentiated cells were also obsrved. The number of interstitial cells and the average volume of interstitial cells also increased, from which we can deduce that these two last events are important in the enlargement of the interstitial cell cords. These findings suggest that the prefollicular ovary is able to respond to FSH, inducing structural changes both in the ovarian cortex as well as in the subcortical medulla.