Showing papers in "General and Comparative Endocrinology in 2003"

TL;DR: This study for the first time provides substantial information about metabolism and excretion of corticosterone in urine and feces of mice and is the first demonstrating a significant impact of the animals' sex and the time of day.

TL;DR: Neuropeptides of the adipokinetic hormone (AKH) family regulate inter alia mobilisation of various substrates from stores in the fat body of insects during episodes of flight.

TL;DR: The molecular and biochemical responses evident in the liver of trout imply changes favouring tissue responsiveness to glucocorticoids and may be a mechanism to offset GR protein downregulation evident with chronic cortisol stimulation in rainbow trout.

TL;DR: Among the potential growth factors examined in this study, IGFI and FGF2 were identified as candidate genes whose expression may contribute to muscle compensatory growth induced by refeeding.

TL;DR: Levels of cortisol metabolites in male African elephant bulls showed that in each male levels of these cortisol metabolites were not elevated during periods of musth, suggesting that in the African elephant musth is generally not associated with marked elevations in glucocorticoid output.

TL;DR: It is suggested that high winter glucocorticoid levels may act via catabolic function during adaptation of deer to cold winter month when resources are limited, and be a source of error when estimating mean hormone levels within a population.

TL;DR: The results suggest that subordinate rainbow trout chronically maintain high levels of CRF mRNA during social stress and that NPY may be involved in the control of the stress axis in trout.

TL;DR: This is the first measurement of the distribution of the activity of a steroidogenic enzyme in the sea bass, an established model in comparative endocrinology and establishes the basis for further comparative studies of certain androgen-mediated actions through locally formed estrogen in both central and peripheral targets.

TL;DR: The results from phylogenetic analysis suggest that the evolution of this group of neuropeptides occurs in a manner similar is to the gene duplication and mutation events hypothesized for the origin of the prolactin and growth hormone gene family of the vertebrate pituitary system.

TL;DR: It is demonstrated that ambient temperature significantly affected photoperiodically induced gonadal development and regression in these birds and the endocrine mechanisms underlying these effects require further study.

TL;DR: The results suggest that the autocrine/paracrine expression of IGF1 and IGF2 in muscle is not a key regulator of the growth promoting effect of temperature, and temperature seems to promote growth through IGF1 secretion by the liver following GH stimulation, and impairment of nutritional status would prevent the IGF1 stimulation by temperature.

TL;DR: It is concluded that zebrafish express just two forms of GnRH in a site-specific manner within the brain, and that sGnRH is the hypophysiotropic GnRH form.

TL;DR: The demonstration that adrenal activity can be detected by the assay is a prerequisite that ecologically meaningful levels of imposed stress can be validated and non-invasive measurements of fecal metabolites are a promising perspective to monitor stress in birds.

TL;DR: Results support the utility of C. latirostris, a species in which sex determination is temperature dependent, as a tool in assessing estrogenic activity in vivo and as a sentinel to monitor EDs in aquatic environment.

TL;DR: Results show that several EDCs tested in this study target qTTR rather than qTR LBD, and that diethylstilbestrol was the most powerful inhibitor of [125I]T3 binding toqTTR.

TL;DR: It is concluded that BPA at the concentrations examined affects both embryonic development and larval metamorphotic changes in Xenopus laevis blastulae.

TL;DR: It is proposed that the hyperglycemia and insulin resistance observable in chickens is associated with their possible deficiency of GLUT4, a major insulin-responsive transporter in mammals, which is deficient in these animals.

TL;DR: It is demonstrated that the pituitary of sea bass contains two gonadotropic hormones and that both gonadotropins are probably involved in the control of gametogenesis, gamete maturation, and spermiation.

TL;DR: The results from this storage condition were robust in terms of practical questions asked of the data: fE and fP values still reflected pregnant versus non-pregnant states in baboon females; a fGC profile constructed by age class resembled that created from the samples from the initial condition, although slightly inflated across age classes; and there were only moderate changes in relative fT concentrations across adult males.

TL;DR: It is of interest to establish the presence and function(s) of GnRH in invertebrate species for possible insights in the pre-vertebrate evolution of the GnRH/ reproduction relationship.

TL;DR: This study describes for the first time the induction of avUCP mRNA expression by low temperature in chickens, as it has been previously shown in ducklings, and supports the possible involvement of av UCP in avian thermogenesis.

TL;DR: The more pronounced disturbance of a broad range of indicators of stress in confined LR fish, compared to HR fish, throws doubt on the magnitude of the cortisol response being the primary driver of these differences.

TL;DR: The results suggest that glucocorticoid metabolites may not be evenly distributed in white-tailed deer feces and researchers are urged to homogenize the entire fecal mass before removing a sub-sample of fecal material for analysis.

TL;DR: The results are consistent with the idea that elevated corticosterone levels inhibit reproduction, but contrast with studies of other oviparous vertebrates in relation to the role of cortic testosterone in regulating egg and clutch size.

TL;DR: CAT D is suggested as a novel bioindicator of the presence of endocrine-disrupting substances in the environment, and HSP70, the Heath Shock Protein 70, was found to be affected by all the toxicant compounds employed in the study; this protein protects cells against harmful conditions by binding and refolding damaged proteins.

TL;DR: It is unlikely that maternal androgens are a key factor in the avian sex determination mechanism, as testosterone levels in chicken eggs do not change with incubation period.

TL;DR: Growth hormone and corticosterone down-regulated cG HS-R1a and cGHS-R 1c mRNA expression within 60 min of exposure, whereas growth hormone-releasing factor 1-29 (1 microM) only reduced cGHM1a mRNA expression after 60min, whereas after 1h levels returned to control values.

TL;DR: There was no correlation between plasma steroid levels and the degree of progress during the early phases of gonadal development in autumn, suggesting other factor such as direct action of GtH(s) or mediating substance other than sex steroids for these phases.

TL;DR: The ability of even young kestrel chicks to elevate corticosterone levels in response to stress suggests that they may be able to physiologically cope with food shortages associated with unpredictable food resources and minimize these negative effects on rapid growth and development in young birds.

TL;DR: The Lusitanian toadfish has group synchronous oocytes, which grow from November until June-July when they are released probably as a single batch, and changes in the gonadosomatic index of males paralleled the females but started to drop slightly earlier, suggesting a role for 11-KT in the development of structures important for reproductive behaviour.