Robeck T R, Amaral R S, da Silva V M F, Martin A R, Montano G A, Brown J L
Species Preservation Laboratory, SeaWorld Parks and Entertainment, 2595 Ingraham Rd, San Diego, CA 92109, USA.
Federal Institute of Education, Science and Technology of Amazonas-IFAM/CMZL, Av. Cosme Ferreira 8045, Manaus 69086-475, Brazil.
Conserv Physiol. 2019 Aug 1;7(1):coz041. doi: 10.1093/conphys/coz041. eCollection 2019.
This study was conducted to characterize immunoreactive thyroid hormone concentrations in wild Amazon river dolphins, also called boto () by age group, sex, pregnancy and lactation status, and to determine if thyroid hormone concentration differences could be detected between pregnant females with and without successful parturition outcomes. Radioimmunoassays were used to analyse total and total in 182 serum samples collected from 172 botos living in the Mamirauá Sustainable Development Reserve, in the Brazilian Amazon from 2003 through 2015. Age significantly affected t and t concentrations in males, with values in immature males and females being significantly lower than those in adult males, whereas no age effects were noted between immature females and adult non-pregnant, non-lactating females. Significant sex differences were noted in t concentrations between immature males and females and in t concentrations between adult males and females. These resulted in significant differences in the t :t ratio between males and females within the immature and adult groups. Lactating and non-pregnant adult females had significantly higher t concentrations than pregnant females, and this difference was primarily driven by a 12% drop in t concentrations during the last two-thirds of pregnancy. No differences in thyroid hormone concentrations were detected between females diagnosed as pregnant and later found to have or not have a live calf. These results are the first to define thyroid hormone reference intervals and normal physiological variations in a wild population of river dolphins.
本研究旨在按年龄组、性别、妊娠和泌乳状态，对野生亚马逊河豚（也称为博托河豚）体内免疫反应性甲状腺激素浓度进行特征描述，并确定能否检测出成功分娩和未成功分娩的怀孕雌性之间甲状腺激素浓度的差异。采用放射免疫分析法，对2003年至2015年期间从巴西亚马逊马米拉瓦可持续发展保护区的172头博托河豚采集的182份血清样本中的总三碘甲状腺原氨酸（T₃）和总甲状腺素（T₄）进行分析。年龄对雄性的T₃和T₄浓度有显著影响，未成熟雄性和雌性的值显著低于成年雄性，而未成熟雌性与成年未孕、未泌乳雌性之间未发现年龄效应。未成熟雄性和雌性之间的T₃浓度以及成年雄性和雌性之间的T₄浓度存在显著性别差异。这导致未成熟组和成年组内雄性和雌性的T₃:T₄比值存在显著差异。泌乳的成年雌性和未孕成年雌性的T₄浓度显著高于怀孕雌性，这种差异主要是由怀孕最后三分之二阶段T₄浓度下降12%所致。在被诊断为怀孕、后来发现产下或未产下活仔的雌性之间，未检测到甲状腺激素浓度的差异。这些结果首次确定了野生河豚种群的甲状腺激素参考区间和正常生理变异。
