Hypergravity disruption of homeorhetic adaptations to lactation in rat dams include changes in circadian clocks.

Altered gravity load induced by spaceflight (microgravity) and centrifugation (hypergravity) is associated with changes in circadian, metabolic, and reproductive systems. Exposure to 2-g hypergravity (HG) during pregnancy and lactation decreased rate of mammary metabolic activity and increased pup mortality. We hypothesize HG disrupted maternal homeorhetic responses to pregnancy and lactation are due to changes in maternal metabolism, hormone concentrations, and maternal behavior related to gravity induced alterations in circadian clocks.

In a hypergravity environment neonatal survival is adversely affected by alterations in dam tissue metabolism rather than reduced food intake.

Exposure of rat dams to hypergravity during pregnancy is associated with increased pup mortality, reduced food intake, and decreased rates of glucose oxidation and lipogenesis in mammary tissue. We hypothesized that increased pup mortality is due to changes in maternal metabolism and not to reduced food intake of dams. Effects of hypergravity on rate of glucose oxidation and lipogenesis in mammary, liver, and adipose tissue were measured in rat dams centrifuged at 2.