Thyroidal inhibition following diverse stress in soft-shelled turtle,Lissemys punctata punctatabonnoterre

Abstract

The current study was undertaken to ascertain the effects of diverse stress on thyroid activity in soft-shelled turtles, Lissemys punctata punctata. The findings revealed that starvation (10 days), dehydration (10 days) or exposure to electric shock (12 volts for 15 seconds at an interval of 30 min for 3 h) caused significant decrease in the body weight (except in electric shock), relative weight, peripheral and central epithelial heights of the follicles and peroxidase activity of the thyroid gland of turtles. The degree of change in the values of these parameters was nearly same in all the stress experiments, indicating that there is not much difference in the degree of thyroid responses to diverse stress in turtles. It is suggested that these stressors might have exerted their actions on thyroid activity presumably indirectly via adrenal medulla and/or substance in metabolic stress (starvation and dehydration) and via hypothalamo-hypophysial-adrenocortical axis in non-metabolic stress (electric shock) in Lissemys turtles.

Moving house: long-term dynamics of corticosterone secretion are unaltered in translocated populations of a rare reptile (the tuatara,Sphenodon punctatus)

“…Porteous and Mullan (2013) report that New Zealand's South Island (close to where Stephens Island is located) was not affected as severely as the North Island, and better hydration in the Cape Kidnappers population was probably achieved through provision of supplementary water sources (L. Anderson, personal observation). Reduced body condition has been observed in dehydrated/water-restricted reptiles, including snakes ( Dupoue et al ., 2014 ; Lillywhite et al ., 2014 ), lizards ( Summers and Norman, 1988 ; Dunlap, 1995 ; Davis and DeNardo, 2009 , 2010 ), alligators ( Lance et al ., 2010 ) and turtles ( Ray et al ., 2004 , 2008 ; van de Merwe et al ., 2013 ). Clearly, information on relationships among water availability/dehydration, body condition, stress and CORT secretion is lacking and should be considered in light of imminent ­climate change.…”

Corticosterone secretion in tuatara (Sphenodon punctatus): Influential factors and conservation applications

“…remaining active during drought) can lead to biased analysis of stress in natural populations. Burrowing in tuatara reduces water loss by up to three times the rate experienced when emerged (Cree, 2014) Lillywhite et al, 2014), lizards (Davis and DeNardo, 2009;Davis and DeNardo, 2010;Dunlap, 1995;Summers and Norman, 1988), alligators (Lance et al, 2010), and turtles (Ray et al, 2004;Ray et al, 2008;van de Merwe et al, 2013). Clearly, information on relationships among water availability/dehydration, body condition, stress, and CORT secretion is lacking, and should be considered in light of imminent climate change.…”