JTS : Vol. 32 (2007) , No. 5 December 495-503

DIFFERENTIAL SUSCEPTIBILITY OF RAT EMBRYOS TO METHYL METHANESULFONATE DURING THE PREGASTRULATION PERIOD

Ryohei YOKOI¹⁾²⁾, Satoshi SUDA²⁾, Kazuo KOBAYASHI²⁾, Junji KURODA²⁾, Hiroshi KUSAMA²⁾, Hiroshi KAGAMI³⁾ and Tamao ONO³⁾

1) Interdisciplinary Graduate School of Science and Technology, Shinshu University
2) Toxicology Research Laboratories, Kissei Pharmaceutical Co., Ltd.
3) Faculty of Agriculture, Shinshu University

(Received August 1, 2007)
(Accepted September 7, 2007)

ABSTRACT- The effects of exposure of pregnant rats to methyl methanesulfonate (MMS), an alkylating agent, during the pregastrulation period on embryonic and placental development were investigated. SD rats were treated orally with a single dose of MMS (200 mg/kg) in the morning of gestation days 0, 1, 2, 3, 4, 5, or 6 (GD0 to GD6 groups, respectively). The uterine contents including fetuses and placentas of the dams were examined on gestation day 20. The individual fetuses and placentas were weighed, and the fetuses were examined for external, visceral and skeletal anomalies. The progress of ossification was also evaluated. Both pre- and postimplantation embryonic mortalities were higher in the GD0 group than in the control group. The postimplantation loss was also increased for the GD3, GD4 and GD6 groups. Fetal malformations were rare in survivors of all the MMS-treated groups. Intrauterine growth retardation was apparent for fetuses in groups GD5 and GD6. In addition, placental weight was reduced in the GD6 group, but it was increased in the GD0 group. Effects of MMS on embryonic mortality or on fetal or placental growth were absent or minimal in the GD1 and GD2 groups. These results suggest that the susceptibility of rat embryos to MMS varies during the pregastrulation period.

	本論文を引用する際にご利用ください:
	Ryohei YOKOI, Satoshi SUDA, Kazuo KOBAYASHI, Junji KURODA, Hiroshi KUSAMA, Hiroshi KAGAMI and Tamao ONO: “DIFFERENTIAL SUSCEPTIBILITY OF RAT EMBRYOS TO METHYL METHANESULFONATE DURING THE PREGASTRULATION PERIOD”: J. Toxicol. Sci., Vol. 32: No. 5, 495-503. (2007) .

	doi:10.2131/jts.32.495
	JOI JST.JSTAGE/jts/32.495