Date of Award

Summer 1987

Degree Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Biology

Comments

In rodents the sexual behavior which is displayed in adulthood results from the hormonal environment that is present during some period of early development. In many of the rodent species this development begins prenatally. These rodent species are polytoccous animals; i.e. they carry more than one fetus in the uterine horn at a time. Variations in behavior are reported to occur due to positioning in the uterus with respect to siblings of the opposite sex. The variations are proposed to result from hormonal variations brought about by hormonal influences that come from siblings within the same uterine horn. For the influences to occur, the hormones of one fetus must be be able to reach other fetuses within the uterine horn. The circulation through the uterus is a possible route . The hormones from one fetus could enter the uterine vein and then diffuse into the artery to be carried to the rest of the uterine horn. Based on blood flow patterns, the unidirectional spread of hormonal influence seen in rats suggests the possible involvement of the circulation. Another possible route for the transfer of hormones between fetuses is diffusion through the amniotic membrane into neighboring fetuses. The bidirectional spread of hormone influence which is seen in mice suggests the diffusion route. In the hamster a unidirectional, caudal to ovarian, spread of hormone influence has been reported. The following study establishes the blood flow pattern in the uterus of pregnant hamsters. Blood flows in one direction, caudal to ovarian, through the uterine artery. This pattern is consistent on days 13, 14 and 15 of gestation (parturition occurs on day 16). This could account for the influences that have been seen in this species.

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