The endocrine capacity of embryonic chick gonads depleted in germ cells was compared to that of controls to determine whether the somatic elements of germ-cell-depleted gonads will undergo normal functional sex differentiation. Primordial germ cells were removed from early embryos, Hamburger and Hamilton stages 7-11, by excision of the anterior germinal crescent. Embryos were sacrificed at 14 days of incubation, and their gonads were analysed for functional differentiation by: (1) electron microscopy to detect ultrastructural cellular morphology characteristic of steroid-secreting cells (2) growth in cell culture to detect development of characteristic cell morphologies; (3) radioimmunoassay of cell-culture media to detect androgens and oestrogens (androstenedione and oestradiol 17 β) secreted by gonadal cells; and (4) measurement of steroid levels produced by cultures treated with human chorionic gonadotropin (hCG) to detect the ability of gonodal cells to increase steroid production in response to gonadotropin stimulation. As a bioassay of gonadal endocrine activity, a gross morphological analysis was performed on the genital ducts, the development of which is ovary-dependent in females and testis-dependent in males. This study demonstrated that both male and female embryonic gonads exhibit normal functional differentiation following a significant reduction in the number of primordial germ cells. These results confirm and extend our previous findings that morphological differentiation of sterile embryonic gonads is normal (McCarrey and Abbott, 1978). It is concluded from the present study that a normal complement of germ cells is not essential to either morphological or functional sex differentiation of the somatic elements of the embryonic ovary or testis, thus arguing against any inductive role for the germ cells in this process.
|Original language||English (US)|
|Number of pages||14|
|Journal||Journal of Embryology and Experimental Morphology|
|State||Published - 1982|
ASJC Scopus subject areas
- Developmental Biology
- Cell Biology