Browsing by Subject "Hypothyroidism"
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- PublicationOpen AccessChanges of the salivary and serum proteome in canine hypothyroidism(Elsevier, 2024-01) González Arostegui, L. G.; Muñoz Prieto, Alberto; Rubio, C. P.; Cerón, J. J.; Bernal, L.; Rubić, I.; Mrljak, V.; González Sánchez, J. C.; Tvarijonaviciute, Asta; Medicina y Cirugía AnimalIn this study, changes in salivary and serum proteome of dogs with hypothyroidism were studied using tandem mass tags (TMT) labelling and liquid chromatography-mass spectrometry (LC-MS/MS). Saliva and serum proteome from 10 dogs with hypothyroidism were compared with 10 healthy dogs. In saliva, a total of seven proteins showed significant changes between the two groups, being six downregulated and one upregulated, meanwhile, in serum, a total of six proteins showed significant changes, being five downregulated and one upregulated. The altered proteins reflected metabolic and immunologic changes, as well as, skin and coagulation alterations, and these proteins were not affected by gender. One of the proteins that were downregulated in saliva, lactate dehydrognease (LDH), was measured by a spectrophotometric assay in saliva samples from 42 dogs with hypothyroidism, 42 dogs with non-thyroid diseases and 46 healthy dogs. The activity of LDH was lower in the saliva of hypothyroid dogs when compared to non-thyroid diseased dogs and healthy controls. This study indicates that canine hypothyroidism can produce changes in the proteome of saliva and serum. These two sample types showed different variations in their proteins reflecting physiopathological changes that occur in this disease, mainly related to the immune system, metabolism, skin and coagulation. In addition, some of the proteins identified in this study, specially LDH in saliva, should be further explored as potential biomarkers of canine hypothyroidism.
- PublicationOpen AccessComparison of testis structure, function and thyroid hormone levels in control C57BL/6 mice and anti-mullerian hormone over expressing mice(Murcia: F. Hernández, 2010) Chamindrani Mendis-Handagama, S.M.L.; Siril Ariyaratne, H.B.; Fecteau, Kellie A.; Grizzle, Judith M.; Jayasundera, Nilanthi K.Anti-Mullerian hormone (AMH) is considered as a negative regulator of postnatal Leydig cell (LC) differentiation, because AMH over expressing mice (Mt-hAMH mice) testes are deficient in LC. Therefore, in the present study Mt-hAMH mice was used as a model to examine the process of postnatal LC differentiation. Testis structure-function studies were performed in age-matching Mt-hAMH and C57BL/6 (controls) mice; testicular components were quantified and circulating testosterone and thyroid hormone levels (thyroxine/T4 and triiodothyronine/T3; necessary for postnatal LC differentiation) were determined. Results revealed that Mt-hAMH mice were heavier and their testis weights were smaller compared to controls. Mast cells were present in Mt-AMH testis interstitium, but absent in controls. The absolute volumes of seminiferous tubules (ST), testis interstitium, LC and blood vessels per testis were lower and lymphatic space was higher in Mt-hAMH mice than in controls (p<0.05). The average cell LC volume and their number per testis, ST length, plasma testosterone, luteinizing hormone-stimulated testosterone secretion per testis and per LC in vitro, plasma T4 and T3 were significantly lower in Mt-hAMH mice compared to controls (p<0.05). Increased body weight in Mt-hAMH mice could be attributed to the reduced T4 and T3. Reduced testis weight in Mt-AMH mice is explained by the reduced ST volume in them. Reduced plasma testosterone, testicular and LC testosterone secretion in vitro in Mt-hAMH mice can be explained by the reduced number, size and steroidogenic potential of LC in Mt-hAMH mice. Study revealed several structure-function deficiencies in Mt-AMH mouse compared to controls, which were not documented in previous investigations. As hypothyroidism causes arrest in postnatal LC differentiation, it is suggested that the reduced LC number in Mt-hAMH testes could be at least in part due to their reduced thyroid hormone levels. However, latter concept needs to be further tested in future investigations.
- PublicationOpen AccessEffects of hypothyroidism on anti-mullerian hormone expression in the prepubertal rat testis(Murcia : F. Hernández, 2008) Chamindrani Mendis-Handagama, S.M.L.; Siril Ariyaratne, H.B.Differentiation of adult Leydig cells (ALC) in the prepubertal rat testis is stimulated by thyroid hormone (Thy) and inhibited by the Anti-Mullerian Hormone (AMH) produced by the immature Sertoli cell (SC). As Thy induces SC maturation in the prepubertal rat testis, we hypothesized that Thy stimulation of ALC differentiation is mediated via inhibition of AMH production by the SC with their maturation. If this hypothesis is true, AMH production by the prepubertal Sertoli cells in hypothyroid rats should not decline immediately after birth as in euthyroid rats, but should be maintained throughout the hypothyroid period at a similar or higher level to that of day 1 rats. This concept was tested using control rats of postnatal days (pd) 1, 7 and 14 and hypothyroid (fed 0.1% propyl thiouracil/PTU to lactating mothers) rats of pd7 and pd14. Presence of AMH in SC was examined by immunocytochemistry for AMH. Results demonstrated that testes of pd1 rats had intense AMH positive labeling exclusively in cytoplasm of SC. In testes of pd7 and pd14 control and PTU rats, a positive but weak labeling was also observed in cytoplasm of some SC; Germ cells and testicular interstitial cells were negative for AMH at all tested ages in both experimental groups. These findings suggest that AMH production by the prepubertal SC is independent of Sertoli cell maturation and not regulated by Thy. Therefore, Thy regulation of ALC differentiation in the prepubertal rat testis is unlikely to be mediated via inhibition of AMH produced by the SC with their maturation.
- PublicationOpen AccessEffects of hypothyroidism on the ultrastructure of rat pancreatic acinar cells: a stereological analysis(Murcia : F. Hernández, 1991) Blanco-Molina, A.; González-Reyes, J.A.; Torre-Cisneros, J.; López-Miranda, J.; Nicolás, M.; Pérez-Jiménez, F.The morphological and stereological characteristics of the exocrine pancreas subcellular organelles from healthy and thyroidectomized rats have been studied. The acinar tissue from hypothyroid rats showed an interstitial edema and evidence of degenerative processes. Stereological parameters of zymogen granules were significantly reduced in thyroidectomized rats. The hypothyroidism induced degenerative changes in the pancreatic acinar cells as well as a decrease in the number and size of the zymogen granules. These modifications probably cause functional alterations.
- PublicationOpen AccessEffects of long-term hypothyroidism in the morphology and synaptic organization of cerebellar ectopic granule cells(Murcia : F. Hernández, 1988) Madeira, M.D.; Azevedo, F.P.; Paula-Barbosa, M.M.Abundant ectopic granule cells scattered in the cerebellar molecular layer have been observed in 30- day-old hypothyroid rats. Their morphological features indicate that they must be regarded as mature heterotopic cells arrested during their migration towards the granular layer. As their impoverished dendritic trees are identical to those seen in controls, it is unlikely that the lack of thyroid hormones played a major role in the deficient dendritic outgrowth. The study of 180-day-old hypothyroid rats revealed that although ectopic granule cells remained quite numerous, their number per unit surface was lesser than in the 30-day-old hypothyroid group. This finding may be related to the capacity displayed by heterotopic neurons to establish synaptic contacts with the components of the molecular layer. This was inferred by the presente of a peculiar synaptic cell investment formed by axosomatic and somatodendritic contacts in 180-day-old hypothyroid rats which shows that the surviving ectopic granule cells manage to adapt to an adverse milieu.
- PublicationRestrictedRole of thyroid hormones in the maturation and organisation of rat barrel cortex(Elsevier, 2001-11-23) Berbel Navarro, Pere; Ausó Monreal, Eva; García Valesco, José Victor; Molina Gallego, María Luisa; Camacho, Miguel; Bioquímica y Biología Molecular B e InmunologíaThe influence of thyroid hormones on cortical development was analysed in rat somatosensory cortex. Maternal and foetal hypothyroidism was induced and maintained by methimazole treatment from embryonic day 13 onwards. 5-Bromo-2′-deoxyuridine (BrdU) labelling in hypothyroid rats showed that cell positioning during corticogenesis followed an inside-out pattern. The radial neurogenetic gradients were more diffuse at all ages with respect to normal rats due to the inappropriate location of many cells, including those of the subcortical white matter. Most (62%) of the cells in the subcortical white matter of hypothyroid rats were labelled at embryonic day 15. Nissl staining of the primary somatosensory cortex showed blurred cortical layer boundaries and an abnormal barrel cytoarchitecture. Cytochrome oxidase and peanut agglutinin staining showed that the tangential organisation of the posteromedial barrel subfield and its layer IV specificity was not lost in hypothyroid rats. However the temporal pattern of peanut agglutinin labelling was delayed 3–4 days with respect to normal rats. In hypothyroid rats, the total barrelfield tangential area was reduced by 27% with respect to normal. The total tangential barrel area, corresponding to peanut agglutinin-negative labelling, occupied 77% of the barrelfield area and only 66% in hypothyroid rats. This reduction was larger with cytochrome oxidase staining where the total barrel area occupied 69% of the barrelfield area in normal and 46% in hypothyroid rats. Our data stress the importance of maternal and foetal thyroid hormones during development, and demonstrate the irreversible effects that maternal and foetal hypothyroidism may have on the intrinsic organisation and maturation of the neocortex.
- PublicationRestrictedUntargeted metabolomic profiling of serum in dogs with hypothyroidism(Elsevier, 2021-01-30) Muñoz-Prieto, Alberto; González-Aróstegui, Luis; Rubic, Ivana; Cerón, José Joaquín; Tvarijonavicite, Asta; Horvatic, Anita; Mrljak, Vladimir; Medicina y Cirugía AnimalHypothyroidism is one of the most commonly diagnosed endocrine disease in dogs. The clinical signs are caused by a deficiency of the active thyroid hormones triiodothyronine (T3) and thyroxine (T4) and have a negative impact on dog’s quality of life. We hypothesized that serum metabolic profile varies between healthy dogs and dogs with hypothyroidism. Twenty serum samples from dogs with hypothyroidism and 20 from healthy dogs were used for untargeted metabolomics analysis performed by LC/MS analysis. Fifteen metabolites showed significant changes between hypothyroid and healthy dogs, being the pentose phosphate pathway (PPP), aminoacyl-tRNA biosynthesis and pyrimidine metabolism the principal pathways altered in hypothyroidism. Specifically, metabolites such as D-gluconic acid and L-Isoleucine may potentially act as biomarkers of disease.