..., the ophiuroid has nearly completed metamorphosis and will shortly settle and discard the anterolateral arms (stage 5). (B) Thyroxine-exposed larvae (10 –7  mol l −1 T4) displayed a reduced rate of metamorphic development, with hydrocoel development stalling at stage 1/2. Despite the reduced hydrocoel...

... are transferred from mothers to offspring ( Ruuskanen and Hsu, 2018 ). Variation in exposure to prenatal thyroid hormones (T3, triiodothyronine, and T4, thyroxine) could influence telomere length via several mutually non-exclusive proximate pathways. (i) Prenatal THs can stimulate growth (although results...

... urchin larvae accelerate the formation of juvenile structures in response to thyroxine (T4) treatment, while reducing their larval arm length. The mechanisms underlying larval arm reduction are unknown and we hypothesized that programmed cell death (PCD) is linked to this process. To test this hypothesis...

... should be able to transmit the hormonal signals independent of their own hormonal status. However, the ability to regulate hormone transfer to the next generation is under debate. We studied the transfer of thyroid hormones (THs) to eggs in a bird model. We elevated thyroxine (T 4 , the prohormone...

... in summer and winter Fig. 3. Relationship between thyroid hormones (THs) and FMR in Shetland pony mares. Regression between TH levels [total thyroxine (ng dl −1 ), tT 3 : A,C; total triiodothyronine (μg dl −1 ), tT 4 : B,D] and FMR [MJ day −1 : A,B; mass-independent FMR, residuals...

... pups ( N =5–7 per week). Fasting did not decrease the concentrations of plasma thyroid stimulating hormone, total triiodothyronine (tT 3 ), free T 3 , total thyroxine (tT 4 ) or free T 4 , suggesting that the hypothalamic–pituitary–thyroid axis is not suppressed, but rather maintained during fasting...

... for investigating adaptive changes in visual pigment composition. * Author for correspondence (e-mail: [email protected] ) 23 4 2008 © The Company of Biologists Limited 2008 2008 rhodopsin porphyropsin thyroxine fish vision opsin gene sequence expression PCR MSP...

... variation in this trait may affect other energetic processes, and potentially fitness. Here, we examine three potential proximate correlates of variation in SMR:organ mass, serum T4 thyroxine and relative mitochondrial content, using flow cytometry. Body-mass-adjusted kidney mass correlated with SMR...

... be completely lost. Both smoltification and the transition to sexual maturity are regulated, in part, by the hormone thyroxine. Thyroxine treatment of juvenile Oncorhynchus mykiss results in precocial developmental changes that mimic smoltification, including a reduction of ultraviolet sensitivity. However...

... (ed. P. A. Raymond , S. S. Easter , Jr and G. M. Innocenti ), pp. 29 – 39 . New York : Plenum Press . Browman , H. I. and Hawryshyn , C. W. ( 1992 ). Thyroxine induces a precocial loss of ultraviolet photosensitivity in rainbow trout ( Oncorhynchus mykiss...