Evidence for placental transfer of maternal corticosterone in a viviparous lizard

Itonaga, Keisuke; Wapstra, Erik; Jones, Susan

doi:10.1016/j.cbpa.2011.05.028

Cited by 14 publications

(8 citation statements)

References 61 publications

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“…These animals were collected at Pulchella Nursery, Tasmania, Australia (42°36′S, 147°40′E) from mid November until the end of December (i.e., mid/late gestation) in the summer of 2007. In Tasmania, ovulation occurs in mid/late October and parturition occurs in early January (Itonaga et al, , b). The animals were held for no more than 3 days in laboratory terraria before experimentation.…”

Section: Methodsmentioning

confidence: 99%

A Novel Pattern of Placental Leucine Transfer During Mid to Late Gestation in a Highly Placentotrophic Viviparous Lizard

Itonaga

Wapstra²,

Jones

2012

J Exp Zool Pt B

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Placentotrophy is the nourishment of embryos by resources provided via the placenta during gestation. The magnitude and timing of placental nutrient support during pregnancy are important for embryonic growth, especially in highly placentotrophic animals such as mammals. However, no study has yet investigated how placental organic nutrient support may change during pregnancy in highly placentotrophic viviparous reptiles. Amino acids are essential nutrients for embryonic growth and leucine is a common amino acid. The magnitude and timing of placental leucine transfer may affect embryonic growth and mass and, therefore, offspring phenotype. In this study, female Pseudemoia entrecasteauxii, a highly placentotrophic viviparous skink, were collected throughout gestation. We injected (3)H-leucine into these gravid females and assessed the transfer of (3)H-leucine into maternal compartments (i.e., the blood and the liver), and into embryonic compartments (i.e., the embryo, the yolk, and the amniotic fluid). At either 60 or 120 min post-injection, the radioactivity in each sample was extracted and then counted, and the transfer ratio was calculated. Our results provide direct evidence that circulating maternal leucine passes through the placenta into the embryos in this species. The relative rate of placental leucine transfer did not alter during mid to late gestation. This suggests the steady somatic growth of the embryos during mid-late pregnancy is dependent upon the placental transfer of nutrients rather than yolk stores. This pattern of placental nutrient support may determine offspring body size at birth and, therefore, offspring fitness in P. entrecasteauxii.

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Section: Methodsmentioning

confidence: 99%

A Novel Pattern of Placental Leucine Transfer During Mid to Late Gestation in a Highly Placentotrophic Viviparous Lizard

Itonaga

Wapstra²,

Jones

2012

J Exp Zool Pt B

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“…However studies on viviparous vertebrates are urgently required. In viviparous vertebrates, the placenta allows transfer of maternal hormones to the embryo, [10][11][12] while placental hormone synthesis is critical to embryonic development. 12,13 Therefore the cumulative effects of disruption of maternal and placental endocrine function have the potential to magnify the effects of EDCs on the developing embryos of viviparous species.…”

Section: Introductionmentioning

confidence: 99%

“…32,33 The intermediate Types II and III exhibit varying degrees of placental complexity and dependence upon yolk as a source of embryonic nutrition. [27][28][29][30][31] Viviparous reptiles are therefore of particular interest in EDC studies due to the multiple pathways through which EDCs may affect development: via altered maternal endocrine signals transferred to the embryo via the yolk 34 or the placenta; 10,11,35 by altered placental function 36 or via direct embryonic contamination via the yolk or the placenta. However, to date there have been no studies of the effects of EDCs on reproductive function in viviparous reptiles.…”

Section: Introductionmentioning

confidence: 99%

Atrazine disrupts gonadal development in a live-bearing lizard

Parsley

Wapstra

Jones

2015

Endocrine Disruptors

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Atrazine (ATZ) is an endocrine disruptor that increases aromatase activity. In viviparous (live-bearing) vertebrates, embryos may be exposed to endocrine disruptors via the placenta. Studies of the effects of ATZ in viviparous amniotes have focused on rodents, which are relatively insensitive to ATZ: studies on other viviparous amniotes are therefore required. We aimed to determine the effects of gestational exposure to a single dose of ATZ at 10 ppb on gonadal development in a viviparous skink, Niveoscincus metallicus. Pregnant skinks were exposed to ATZ, the synthetic estrogen diethylstilbestrol (DES) (positive control), vehicle solvent or no treatment. Gonads were examined histologically at birth. Females born to ATZ and DES exposed mothers were more likely to exhibit ovaries with abnormal oocytes than were females whose mothers received vehicle solvent or no treatment. Males born to ATZ and DES exposed mothers were equally more likely to exhibit testes devoid of germ cells with reduced organization of seminiferous tubules (ST) compared to males born to mothers receiving vehicle solvent or no treatment. However, ATZ treatment significantly increased the number of male neonates born with testicular lesions compared to males born to mothers in any other group. We conclude that atrazine disrupts gonadal differentiation in the viviparous lizard, N. metallicus. The similar effects of DES and ATZ suggest that the developmental effects of ATZ in N. metallicus reflect increased estrogen signaling. Atrazine should be used with caution as exposure of wildlife to this EDC is likely to have adverse effects on reproductive health.

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“…They are small matrotrophic viviparous skinks [snout-vent length (SVL) 40–60 mm] and their nutrient provisioning for embryonic development is roughly half from the yolk and half via the placenta [21] , [39] . This is an ideal model species to investigate the evolution of matrotrophic reproduction in reptiles; we have previously demonstrated the importance of transfer of nutrients, organic substances and hormones across the placenta [22] , [40] , [41] during embryo development, and here explore the importance of variation in two key environmental factors that affect female energy availability during gestation (temperature and food availability). This species is restricted to cold-temperate regions where food and thermal availability vary annually and seasonally [42] – [45] .…”

Section: Introductionmentioning

confidence: 99%

Effects of Maternal Basking and Food Quantity during Gestation Provide Evidence for the Selective Advantage of Matrotrophy in a Viviparous Lizard

2012

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The evolution of matrotrophy (i.e., direct supply of nutrients by the mother during gestation) may be associated with high maternal energy availability during gestation. However, we lack knowledge about the selective advantages of matrotrophic viviparity (live-bearing) in reptiles. In reptiles, the interaction between body temperature and food intake affect maternal net energy gain. In the present study, we examined the effects of basking and food availability (2 by 2 factorial design) during gestation on offspring phenotype in a matrotrophic viviparous lizard (Pseudemoia entrecasteauxii). Subsequently, we investigated if the maternal effects were context-dependent using offspring growth rate as an indicator of the adaptive significance of matrotrophy. Offspring were exposed either to the same thermal conditions as their mothers experienced or to thermal conditions different from those experienced by their mothers. We provide the first evidence that an interaction between maternal thermal and maternal food conditions during gestation strongly affects offspring phenotype, including date of birth, body size and performance ability, which affect offspring fitness. Offspring growth rate was dependent on offspring thermal conditions, but was not influenced by maternal effects or offspring sex. Matrotrophic viviparity provided gravid females with the means to enhance offspring fitness through greater energetic input to offspring when conditions allowed it (i.e., extended basking opportunity with high food availability). Therefore, we suggest that selective advantages of matrotrophic viviparity in P. entrecasteauxii may be associated with high maternal energy availability during gestation.

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Evidence for placental transfer of maternal corticosterone in a viviparous lizard

Cited by 14 publications

References 61 publications

A Novel Pattern of Placental Leucine Transfer During Mid to Late Gestation in a Highly Placentotrophic Viviparous Lizard

A Novel Pattern of Placental Leucine Transfer During Mid to Late Gestation in a Highly Placentotrophic Viviparous Lizard

Atrazine disrupts gonadal development in a live-bearing lizard

Effects of Maternal Basking and Food Quantity during Gestation Provide Evidence for the Selective Advantage of Matrotrophy in a Viviparous Lizard

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