title: Serum immunoglobulin G concentration in Southern elephant seal, Mirounga leonina (Linnaeus, 1758), from Elephant Island (Antarctica): sexual and adrenal steroid hormones effects.
abstract: 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+/-6.5mg ml(-1)) than in juveniles (7.9+/-4.0mg ml(-1)), but similar to weaned pups (12.0+/-5.0mg 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+/-643.1pmol 1(-1) and 272.7+/-110.0 nmol 1(-1), respectively) than in the juveniles (638.6+/-579.7pmol1(-1) and 152.9+/-97.3nmol 1(-1), respectively) and adults (386.5+/-209.1pmol (-1) and 145.7+/-67.3nmol 1(-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.
authors.affiliation: Programa de Pós-Graduação em Ciências Fisiológicas: Fisiologia Animal Comparada, Fundação Universidade Federal do Rio Grande (FURG), Rio Grande, RS, 96201-900, Brazil.
authors.forename: Ana P S
authors.initials: AP
authors.lastname: Ferreira
authors.forename: Pablo E
authors.initials: PE
authors.lastname: Martínez
authors.forename: Elton P
authors.initials: EP
authors.lastname: Colares
authors.forename: Ricardo B
authors.initials: RB
authors.lastname: Robaldo
authors.forename: Maria E A
authors.initials: ME
authors.lastname: Berne
authors.forename: Kleber C
authors.initials: KC
authors.lastname: Miranda Filho
authors.forename: Adalto
authors.initials: A
authors.lastname: Bianchini
mesh_terms: D000305:Adrenal Cortex Hormones / Q000097:blood*; D000450:Aldosterone / Q000097:blood; D000818:Animals; D004797:Enzyme-Linked Immunosorbent Assay; D004967:Estrogens / Q000097:blood; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006854:Hydrocortisone / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D011374:Progesterone / Q000097:blood; D011863:Radioimmunoassay; D046048:Seals, Earless / Q000097:blood* / Q000254:growth & development / Q000276:immunology*; D012727:Sex Characteristics; D013739:Testosterone / Q000097:blood
chemical_list: D000305:Adrenal Cortex Hormones; D004967:Estrogens; D012739:Gonadal Steroid Hormones; D007074:Immunoglobulin G; D013739:Testosterone; D000450:Aldosterone; D011374:Progesterone; D006854:Hydrocortisone