The effects of somatostatin (SRIF) on the production and release of TSH and its subunits have been investigated in bovine anterior pituitary monolayer cultures. SRIF caused a dose-dependent inhibition of TSH and subunit release by TRH, with a half-maximal effective dose of 3 X 10(-8) M. This effect was time dependent and was greater for TSH than for its subunits. However, the basal release and total production of TSH and its subunits over a 24-h period were not affected by SRIF. The effect of SRIF was additive to that of thyroid hormones in suppressing the release of TSH and its subunits by TRH. A combination of SRIF and thyroid hormone completely suppressed the release of TSH and its subunits by TRH. In contrast, thyroid hormones caused a dose-dependent inhibition of the total production, as well as the release, of TSH and its subunits induced by TRH. Furthermore, thyroid hormones produced a dose-dependent increase (r = 0.81; P less than 0.001) in the effectiveness of a single dose of SRIF in suppressing TSH release by TRH. Analysis of these data revealed that thyroid hormones interacted synergistically with the SRIF effect to suppress TRH-mediated TSH and subunit release.
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http://dx.doi.org/10.1210/endo-112-6-1937 | DOI Listing |
JCEM Case Rep
January 2025
Section of Endocrinology and Investigative Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College, London W12 ONN, UK.
We report a 31-year-old man with diarrhea and tachycardia. Diagnostic workup confirmed raised free thyroid hormones with unsuppressed thyroid stimulating hormone (TSH). Laboratory assay and medication interference were excluded.
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Department of Dermatology, Father Muller Medical College, Mangalore, India.
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November 2024
Department of Clinical Science and Services, The Royal Veterinary College, Hertfordshire, AL9 7TA, UK.
Feline hyperthyroidism (FHT) is a debilitating disease affecting > 10% of elderly cats. It is generally characterised by chronic elevation of thyroid hormone in the absence of circulating TSH. Understanding of the molecular pathogenesis of FHT is currently limited.
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October 2024
Institute of Marine & Environmental Technology, Department of Marine Biotechnology, University of Maryland Baltimore County, Baltimore, MD 21202, USA.
GnRH governs reproduction by regulating pituitary gonadotropins. Unlike most vertebrates, gnrh-/- zebrafish are fertile. To elucidate the role of the hypophysiotropic-Gnrh3 and other mechanisms regulating pituitary gonadotropes, we profiled the gene expression of all individual pituitary cells of wild-type and gnrh3-/- adult female zebrafish.
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September 2024
Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China; Biology Department, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China. Electronic address:
Thyroid stimulating hormone (TSH), a glycoprotein synthesized and secreted from thyrotrophs of the pituitary gland, is composed of a glycoprotein hormone common alpha subunit (CGA) and a specific beta subunit (TSHB). The major biological function of TSH is to stimulate thyroidal follicles to synthesize and secrete thyroid hormones through activating its cognate receptor, the thyroid stimulating hormone receptor (TSHR). In the present study, polyclonal antisera against ricefield eel Tshb and Tshr were generated respectively, and the expression of Tshb and Tshr was examined at mRNA and protein levels.
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