Effects of thyrotropin and thyroid hormones in vivo on thyroid responsiveness to thyrotropin in vitro. 1977

M Zakarija, and J M McKenzie

The thyroid gland of rats fed propylthiouracil is known to be unresponsive in vitro to thyrotropin; to investigate further the underlying mechanism groups of rats were variously treated with propylthiouracil and thyroid hormone or subjected to hypophysectomy. In vitro responsiveness of the thyroids was tested by measuring an increase in the concentration of c AMP when thyrotropin or prostaglandin E1 was added to the medium. Results showed that responsiveness to thyrotropin partially returned with rats fed prophylthiouracil and hypophysectomized 5, but not 2, days before death; hypophysectomy of normal rats led to increased in vitro responsiveness to thyrotropin and this was partially reversed by injections of thyrotropin for a week before death. Administration of thyroid hormone had little effect in these investigations and in vitro responsiveness to prostaglanding E1 was not consistently influenced by any of the in vivo regimens. From this experience we conclude that, at least as studied in vitro, circulating thyrotropin has a significant role in modulating responsiveness of the thyroid to thyrotropin.

UI MeSH Term Description Entries
D007016 Hypophysectomy Surgical removal or destruction of the hypophysis, or pituitary gland. (Dorland, 28th ed) Hypophysectomies
D008297 Male Males
D011441 Propylthiouracil A thiourea antithyroid agent. Propythiouracil inhibits the synthesis of thyroxine and inhibits the peripheral conversion of throxine to tri-iodothyronine. It is used in the treatment of hyperthyroidism. (From Martindale, The Extra Pharmacopeoia, 30th ed, p534) 6-Propyl-2-Thiouracil,6 Propyl 2 Thiouracil
D000242 Cyclic AMP An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH. Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D013961 Thyroid Gland A highly vascularized endocrine gland consisting of two lobes joined by a thin band of tissue with one lobe on each side of the TRACHEA. It secretes THYROID HORMONES from the follicular cells and CALCITONIN from the parafollicular cells thereby regulating METABOLISM and CALCIUM level in blood, respectively. Thyroid,Gland, Thyroid,Glands, Thyroid,Thyroid Glands,Thyroids
D013963 Thyroid Hormones Natural hormones secreted by the THYROID GLAND, such as THYROXINE, and their synthetic analogs. Thyroid Hormone,Hormone, Thyroid,Hormones, Thyroid
D013972 Thyrotropin A glycoprotein hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Thyrotropin stimulates THYROID GLAND by increasing the iodide transport, synthesis and release of thyroid hormones (THYROXINE and TRIIODOTHYRONINE). Thyrotropin consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the pituitary glycoprotein hormones (TSH; LUTEINIZING HORMONE and FSH), but the beta subunit is unique and confers its biological specificity. Thyroid-Stimulating Hormone,TSH (Thyroid Stimulating Hormone),Thyreotropin,Thyrotrophin,Hormone, Thyroid-Stimulating,Thyroid Stimulating Hormone
D015105 3',5'-Cyclic-AMP Phosphodiesterases Enzymes that catalyze the hydrolysis of CYCLIC AMP to form adenosine 5'-phosphate. The enzymes are widely distributed in animal tissue and control the level of intracellular cyclic AMP. Many specific enzymes classified under this heading demonstrate additional spcificity for 3',5'-cyclic IMP and CYCLIC GMP. 3',5'-Cyclic AMP 5'-Nucleotidohydrolase,3',5'-Cyclic-Nucleotide Phosphodiesterase,CAMP Phosphodiesterase,3',5' Cyclic AMP Phosphodiesterase,3',5'-Cyclic AMP Phosphodiesterase,3',5'-Cyclic Nucleotide Phosphodiesterase,3',5'-Cyclic-AMP Phosphodiesterase,3',5'-Nucleotide Phosphodiesterase,3,5-Cyclic AMP 5-Nucleotidohydrolase,3,5-Cyclic AMP Phosphodiesterase,3',5' Cyclic AMP 5' Nucleotidohydrolase,3',5' Cyclic AMP Phosphodiesterases,3',5' Cyclic Nucleotide Phosphodiesterase,3',5' Nucleotide Phosphodiesterase,3,5 Cyclic AMP 5 Nucleotidohydrolase,3,5 Cyclic AMP Phosphodiesterase,5'-Nucleotidohydrolase, 3',5'-Cyclic AMP,5-Nucleotidohydrolase, 3,5-Cyclic AMP,AMP 5'-Nucleotidohydrolase, 3',5'-Cyclic,AMP 5-Nucleotidohydrolase, 3,5-Cyclic,AMP Phosphodiesterase, 3',5'-Cyclic,AMP Phosphodiesterase, 3,5-Cyclic,Nucleotide Phosphodiesterase, 3',5'-Cyclic,Phosphodiesterase, 3',5'-Cyclic AMP,Phosphodiesterase, 3',5'-Cyclic Nucleotide,Phosphodiesterase, 3',5'-Cyclic-AMP,Phosphodiesterase, 3',5'-Cyclic-Nucleotide,Phosphodiesterase, 3',5'-Nucleotide,Phosphodiesterase, 3,5-Cyclic AMP,Phosphodiesterase, CAMP,Phosphodiesterases, 3',5'-Cyclic-AMP
D051381 Rats The common name for the genus Rattus. Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus

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