title: Adiponectin and Insulin in Gray Seals during Suckling and Fasting: Relationship with Nutritional State and Body Mass during Nursing in Mothers and Pups.
abstract: Animals that fast during breeding and/or development, such as phocids, must regulate energy balance carefully to maximize reproductive fitness and survival probability. Adiponectin, produced by adipose tissue, contributes to metabolic regulation by modulating sensitivity to insulin, increasing fatty acid oxidation by liver and muscle, and promoting adipogenesis and lipid storage in fat tissue. We tested the hypotheses that (1) circulating adiponectin, insulin, or relative adiponectin gene expression is related to nutritional state, body mass, and mass gain in wild gray seal pups; (2) plasma adiponectin or insulin is related to maternal lactation duration, body mass, percentage milk fat, or free fatty acid (FFA) concentration; and (3) plasma adiponectin and insulin are correlated with circulating FFA in females and pups. In pups, plasma adiponectin decreased during suckling (linear mixed-effects model [LME]: T = 4.49; P < 0.001) and the early postweaning fast (LME: T = 3.39; P = 0.004). In contrast, their blubber adiponectin gene expression was higher during the early postweaning fast than early in suckling (LME: T = 2.11; P = 0.046). Insulin levels were significantly higher in early (LME: T = 3.52; P = 0.004) and late (LME: T = 6.99; P < 0.001) suckling than in fasting and, given the effect of nutritional state, were also positively related to body mass (LME: T = 3.58; P = 0.004). Adiponectin and insulin levels did not change during lactation and were unrelated to milk FFA or percentage milk fat in adult females. Our data suggest that adiponectin, in conjunction with insulin, may facilitate fat storage in seals and is likely to be particularly important in the development of blubber reserves in pups.
authors: Marine Biology and Ecology Research Centre, School of Marine Science and Engineering, Plymouth University, Portland Square, Drake Circus, Plymouth, Devon PL4 8AA, United Kingdom; 2Natural Environment Research Council Sea Mammal Research Unit, Gatty Marine Laboratories, Scottish Oceans Institute, University of St. Andrews, St. Andrews, Fife KY16 8LB, United Kingdom.
authors: K A
authors: KA
authors: Bennett
authors: J
authors: J
authors: Hughes
authors: S
authors: S
authors: Stamatas
authors: S
authors: S
authors: Brand
authors: N L
authors: NL
authors: Foster
authors: S E W
authors: SE
authors: Moss
authors: P P
authors: PP
authors: Pomeroy
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D000833:Animals, Suckling; D001835:Body Weight; D004734:Energy Metabolism; D005215:Fasting / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D007328:Insulin / Q000097:blood*; D007774:Lactation / Q000502:physiology*; D008892:Milk / Q000737:chemistry*; D046048:Seals, Earless / Q000502:physiology*
chemical_list: D052242:Adiponectin; D007328:Insulin