Effects of 1,1-bis (p-chlorophenyl)-2,2,2-trichloroethane (DDT) on gonadal development in the chick embryo: A histological and histochemical study.
Environ Res 1984 Dec; 35(2):333-345
Histological and histochemical techniques were used to examine the effects of 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (50293) (DDT) exposure on two distinct stages in chick embryos: a period during primordial germ cell (PGC) migration (after 5 days of incubation), and the midstage of gonadal development (after 12 days of incubation). DDT in olive oil was administered into the yolk sac of unincubated fertile white Leghorn eggs in dosages of 5.0, 10.0, or 20.0 milligrams (mg). After 5 and 12 days of incubation, the gonadal areas were prepared for histological and histochemical examination. There was no significant difference in the number of PGCs aggregating in the gonadal area of 5 day chick embryos exposed to DDT. No apparent inclination toward maleness or femaleness was apparent. In the 12 day group, DDT exposed embryos had a male/female ratio of 22:27 compared to 15:8 for controls. There was no abnormal external development of the chick embryos. After 5 days there were no alterations in the cellular morphology of the gonads. Mitotic activity of PGCs in DDT exposed and control embryos was not substantially different. In the ovaries, the only apparent differences were the number and position of the distended medullary cords in the left ovary; larger numbers were present in exposed embryos. A morphological alteration was present in exposed testes, an increased amount of stroma with a corresponding reduction in the number of seminiferous cords. The distribution and amount of acid- phosphatase (AP) and alkaline-phosphatase (ALP) were similar in exposed and control embryos at 5 days. After 12 days, there was an absence or reduction of AP activity in the ovaries of exposed embryos. Secondary sex cords were devoid of this activity. Ovaries of exposed embryos contained a significantly larger amount of ALP activity than controls. There was no reduction in the mitotic activity of PGCs in the gonadal area of exposed embryos at 5 days. No large wave of degeneration was suggested during the period of migration and gonadal colonization by the PGCs.
NIOSH-Publication; NIOSH-Grant; Laboratory-animals; Enzyme-activity; Histology; Sex-factors; Teratogenesis; Embryotoxicity; Pesticides; Chlorinated-hydrocarbon-insecticides; Reproductive-system-disorders
Louisiana State University, School of Medicine, Department of Anatomy, New Orleans, Louisiana