The effects of fasting and increased feeding on plasma thyroid hormones, glucose, and total protein in sea turtles

The effects of fasting and increased feeding on plasma thyroid hormones, gl ucose, and total protein levels were investigated in immature greens (Chelo nia mydas) and Kemp's ridley (Lepidochelys kempi) sea turtles. Under consta nt temperature, nutritional status affected plasma thyroid hormones and glu cose level, but not protein level in green and Kemp's ridley turtles. Plasm a T-4 in green turtles decreased with deprivation of food, but did not do s o in Kemp's ridleys. Increased feeding did not affect circulating levels of plasma T-4 in either species. Plasma T-3, in contrast, tended to decrease during fasting and increase with refeeding or increased feeding. Blood gluc ose level fell with deprivation of food, but remained constant during incre ased feeding. Sea turtles may use glycogen or lipid during short-term fasti ng as in endothermic vertebrates.