Ontogeny and ultrastructure of somatostatin and calcitonin cells in the thyroid gland of the rat

Alumets, J.; Håkanson, R.; Lundqvist, G.; Sundler, F.; Thorell, Jan I.

doi:10.1007/bf00232763

Cited by 69 publications

(26 citation statements)

References 13 publications

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“…However, it is noteworthy that during maturation ofthe rat, total pancreatic content of insulin, glucagon, and somatostatin gradually increase (39-41), whereas total TRH content decreases. In addition, the decline in pancreatic TRH concentrations in the first few days of life is paralleled by a very similar decrease in the concentration of somatostatin and number of somatostatin-containing cells in the thyroid (42). Whether a similar loss of TRH-containing elements may be simultaneously occurring in the pancreas is unknown.…”

Section: Discussionmentioning

confidence: 99%

Thyrotropin-releasing Hormone in the Systemic Circulation of the Neonatal Rat Is Derived from the Pancreas and Other Extraneural Tissues

Engler¹,

Scanlon²,

Jackson³

1981

J. Clin. Invest.

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A B S T R A C T Thyrotropin-releasing hormone immunoreactivity (IR-TRH) has been detected in the circulation ofthe neonatal rat. This immunoreactivity was demonstrated in purified ethanol extracts of plasma, and was indistinguishable from synthetic TRH using radioimmunoassay and chromatographic criteria. To determine the source of the circulating IR-TRH, tissue concentrations of TRH were analyzed during maturation of the rat. These studies revealed that during the first 10 d oflife, the pancreas contained the greatest concentration of IR-TRH of any organ (pancreas, 289±+35 pg/mg; hypothalamus, 13±3 pg/mg, day 5). Thereafter, pancreatic IR-TRH concentrations declined progressively while hypothalamic concentrations gradually increased (pancreas, 1.2±0.2 pg/mg; hypothalamus, 365±54 pg/mg, adult rat). IR-TRH was also found throughout the gastrointestinal tract but was not detected in the liver; spleen, kidney, or heart. IR-TRH from the pancreas and gastrointestinal tract gave radioimmunoassay binding displacement curves that were parallel to a curve generated with synthetic TRH, and co-migrated with synthetic TRH on Sephadex G-10 and high performance liquid chromatography. In addition, IR-TRH from purified pancreatic extracts was biologically active in that it released thyrotropin and prolactin from rat adenohypophysial cells maintained in monolayer culture. When a total pancreatectomy was performed on the 5th al of life of the rat, mean plasma TRH concentrations were significantly decreased 3 h afterwards (84.±9 vs. 63±7 pg/ml, P < 0.05). Neither the TRH concentrations in the brain, hypothalamus, or gastrointestinal tract, nor the pituitary-thyroid axis were affected by the pancreatectomy.This work was presented in part at the 62nd Annual Meeting of the Endocrine Society, Washington, D. C., 18-20 June 1980.Received for publication 21 July 1980 and in revised form 30 October 1980. 800 However, mean plasma TRH concentrations remained unaltered 3 h after removal of the hypothalamus and extrahypothalamic brain.From these results we conclude the following: (a) the TRH immunoreactivity in the circulation, pancreas, and gastrointestinal tract of the neonatal rat is indistinguishable from synthetic TRH; (b) pancreatic secretion provides a significant contribution to the IR-TRH in plasma, and a proportion of the circulating IR-TRH is derived from other extraneural sites. These findings therefore imply that alterations in hypothalamic and extrahypothalamic brain secretion of TRH are not reflected by changes in levels of this tripeptide in the systemic circulation.

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Section: Discussionmentioning

confidence: 99%

Thyrotropin-releasing Hormone in the Systemic Circulation of the Neonatal Rat Is Derived from the Pancreas and Other Extraneural Tissues

Engler¹,

Scanlon²,

Jackson³

1981

J. Clin. Invest.

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“…Thus, while the frequency for somatostatin-immunoreactive (SS-IR) CC varies in rats throughout their lives, as they are scarce in the foetus, abundant at the time of birth and scarce again in adults (see Figure 6) [33,[95][96][97], the majority of calcitonin immunoreactive (CT-IR) CC in guinea pigs and rabbits are also SS-IR, besides positivity is seen in the parathyroid gland [33]. On the contrary, SS-IR CC are observed very occasionally in normal pig and human thyroid glands [98].…”

Section: Somatostatinmentioning

confidence: 99%

Paracrine Regulation of Thyroid-Hormone Synthesis by C Cells

Fernández-Santos¹,

García-Marín²,

Utrilla³

et al. 2012

Thyroid Hormone

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“…PEARSE (1966PEARSE ( , 1968PEARSE ( , 1969 has long been advocating the amine precursor uptake and decarboxylation (APUD) theory by noting the existence of serotonin (5-HT), an amine, in addition to calcitonin in the parafollicular cells and the ultimobranchial body. The existence of somatostatin, a peptide hormone, in parafollicular cells has also been recently confirmed in a number of animals (HoKFELT et al, 1975;NOORDEN et al, 1977;YAMADA et al, 1977;BUFFA et al, 1979;ALUMETS et al, 1980;KUSUMOTO,1980). Furthermore, the existence of tyrosin hydroxylase (TH), a catecholamine-synthesizing enzyme, in the parafollicular cells of the dog and in the ultimobranchial body of the grass parakeet has been confirmed by the present authors (YAMADA et al, 1983) by using an immunofluorescent method, thus supporting the existence of these cells as being of the neuroectodermal origin suggested by PEARSE .…”

Section: Discussionmentioning

confidence: 84%