Twin Conception in Sheep Leads to Impaired Insulin Sensitivity and Sexually Dimorphic Adipose Tissue and Skeletal Muscle Phenotypes in Adulthood

Abstract

Twins are often born small and early and have increased risk of obesity and diabetes later in life. Twin conception in sheep, regardless of whether the pregnancy continues as twins or is reduced to singleton in early gestation, alters offspring growth trajectory and body composition in young adulthood. We hypothesized that twin conception would result in insulin resistance in adulthood, with insulin-resistant adipose tissue and skeletal muscle phenotypes. At 3 years of age, body weight was not different among singletons, twins, and reductions; females weighed less than males. Singletons were leaner than reductions, with twins intermediate. Twins and reductions had decreased insulin sensitivity compared with singletons (singletons: mean [standard error of the mean]: 4.75 [0.4], twins: 3.34 [0.3], reductions: 3.67 [0.2] mg·I μU-'1·kg-'1·min-'1, P