Daily variation in maternal and fetal weight gain in mice and hamsters

✍ Scribed by Davis, Fred C.

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 834 KB
• Volume: 250
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402500306

✦ Synopsis

Daily variation in maternal and fetal weight gain was measured in hamsters (Mesocricetus auratus) and in mice ( M u s musculus, C57B1) with free access to food or under restricted feeding schedules. Pregnant hamsters with free access to food and water were weighed twice a day and fetuses were collected twice a day from 10.5 to 14.5 days after fertilization. In three experiments, pregnant mice were given free access t o food and water or were allowed food for 12 hours a day or for 6 hours a day. Pregnant mice were weighed twice a day and in the restricted feeding experiments, fetuses were collected every 6 hours from 12.0 to 14.5 days after fertilization. Pregnant mice and hamsters with free access to food showed a daily rhythm in weight gain with greater gain at night. There was no evidence of a daily rhythm in the weight gain of hamster fetuses. Mouse fetuses showed greater weight gain during two 6-hour intervals each day, the second half of each night and the second half of each day. The 12-hour variation was seen in both wet and dry fetal weight. A 24-hour rhythm in fetal growth was previously described in rats (Barr: Teratology, 7:283-288, 1973). Results in rats and mice indicate that fetal growth is modulated on a daily basis. The different periodicity observed in rats and mice might be related to the different ages of the fetuses examined.