Changes in Vitellogenin Expression during Captivity-Induced Stress in a Tropical Anole

Assessment of estrogenic exposure in brown trout (Salmo trutta) in a Swiss midland river: Integrated analysis of passive samplers, wild and caged fish, and vitellogenin mRNA and protein

“…When relating the VTG levels in brown trout to estrogenic loads in the river, possible confounding factors have to be considered. Examples include genetic polymorphisms of the VTG gene [47] or stress, which has been shown to modulate VTG induction in fish [50–52] and, in the present study, may have modified the VTG response of caged fish [31,53]. Another confounding factor that influenced the VTG biomarker response in the present study is the sex of the exposed fish.…”

Chronic captivity stress in wild animals is highly species-specific

“…In house sparrows, Lombardo and Thorpe (2009) found decreased sperm production, reduced testes size and a change in beak color from breeding-season black to wintering brown after 3 months of captivity. Female anole lizards experienced a rapid decrease in plasma vitellogenin (a protein necessary for yolk production) followed by regression of developing follicles (Morales and Sanchez, 1996). In electric fish, behavioral differences between males and females were reduced in captivity until they disappeared or even reversed.…”

Hormonal Regulation of Ovarian Function in Reptiles

“…One group has experimented with GnRH as a means of inducing female receptivity and ovulation in iguanas, with some limited success (Phillips et al, 1987). In captive Anolis pulchellus, Vtg synthesis drops and a marked downregulation of Vtg mRNA levels is observed, but these effects can be alleviated or reversed by treatment with estradiol E 2 (Morales & Sanchez, 1996). In particular, the stress of captivity may severely disrupt the reptilian reproductive cycle via inhibitory effects on plasma concentrations of ovarian steroids .…”