Serum immunoglobulin G concentration in Southern elephant seal, Mirounga leonina (Linnaeus, 1758), from Elephant island (Antarctica): sexual and adrenal steroid hormones effects

• Main Authors: Ferreira, Ana Paula da Silva, Martínez, Pablo Elías, Colares, Elton Pinto, Robaldo, Ricardo Berteaux, Berne, Maria Elisabeth Aires, Miranda Filho, Kleber Campos, Bianchini, Adalto
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2005
• Subjects: Antarctica; Immunoglobulin G; Marine mammal; Mirounga leonine; Steroid hormones; Southern elephant seal; Elephant Island; Antarc*; Elephant Seal; Elephant Seals; Mirounga leonina; Southern Elephant Seal; Southern Elephant Seals
• Online Access: http://repositorio.furg.br/handle/1/388

Serum immunoglobulin G (IgG; indirect enzyme-linked immunosorbent assay), as well as sexual and adrenal steroid hormones’ concentrations (radioimmunoassay) were determined in 63 (male and female) Southern elephant seals (Mirounga leonine) at different developmental stages (weaned pups, juveniles and adults). In females, IgG values (mean _ S.D.) were higher (P < 0.05) in adults (15.9 _ 6.5 mg ml_1) than in juveniles (7.9 _ 4.0 mg ml_1), but similar to weaned pups (12.0 _ 5.0 mg ml_1). Estrogen concentration was higher (P < 0.05) in adults than in the weaned pups. In females, a significant (P < 0.05) correlation (R = 0.4) between serum IgG level and progesterone concentration was observed. In males, testosterone concentration was higher (P < 0.05) in adults than in the juveniles and weaned pups. Aldosterone and cortisol concentrations were higher (P < 0.05) in weaned pups (1056.0 _ 643.1 pmol l_1 and 272.7 _ 110.0 nmol l_1, respectively) than in the juveniles (638.6 _ 579.7 pmol l_1 and 152.9 _ 97.3 nmol l_1, respectively) and adults (386.5 _ 209.1 pmol l_1 and 145.7 _ 67.3 nmol l_1, respectively). These findings indicate that weaned pups are subjected to a higher natural stressful condition in the field. Despite this, humoral immunity, measured through IgG concentration, is not impaired in weaned pups.