Differential responsiveness of somatotrophs to growth hormone-releasing hormone and thyrotropin-releasing hormone during chicken embryonic development

1997 ◽  
Vol 132 (1-2) ◽  
pp. 33-41 ◽  
Author(s):  
Carlton E Dean ◽  
Michelle Piper ◽  
Tom E Porter
Keyword(s):  
Growth Hormone ◽  
Embryonic Development ◽  
Thyrotropin Releasing Hormone ◽  
Growth Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Differential Responsiveness

scholarly journals Pre- and posthatch developmental changes in hypothalamic thyrotropin-releasing hormone and somatostatin concentrations and in circulating growth hormone and thyrotropin levels in the chicken

1998 ◽  
Vol 159 (2) ◽  
pp. 219-225 ◽  
Author(s):  
KL Geris ◽  
LR Berghman ◽  
ER Kuhn ◽  
VM Darras
Keyword(s):  
Growth Hormone ◽  
Embryonic Development ◽  
Present Report ◽  
Thyrotropin Releasing Hormone ◽  
The Other ◽  
Developmental Changes ◽  
Releasing Hormone ◽  
Steep Increase ◽  
Plasma Gh ◽  
Tsh Levels

Thyrotropin-releasing hormone (TRH) and somatostatin (SRIH) concentrations were determined by RIA during both embryonic development and posthatch growth of the chicken. Both TRH and SRIH were already detectable in hypothalami of 14-day-old embryos (E14). Towards the end of incubation, hypothalamic TRH levels increased progressively, followed by a further increase in newly hatched fowl. SRIH concentrations remained stable from E14 to E17 and doubled between E17 and E18 to a concentration which was observed up to hatching. Plasma GH levels remained low during embryonic development, ending in a steep increase at hatching. Plasma TSH levels on the other hand decreased during the last week of the incubation. During growth, TRH concentrations further increased, whereas SRIH concentrations fell progressively towards those of adult animals. Plasma TSH levels increased threefold up to adulthood; the rise in plasma GH levels during growth was followed by a drop in adults. In conclusion, the present report shows that important changes occur in the hypothalamic TRH and SRIH concentration during both embryonic development and posthatch growth of the chicken. Since TRH and SRIH control GH and TSH release in the chicken, the hypothalamic data are compared with plasma GH and TSH fluctuations.

scholarly journals Thyrotropin-Releasing Hormone (TRH) and Somatostatin (SST), but not Growth Hormone-Releasing Hormone (GHRH) nor Ghrelin (GHRL), Regulate Expression and Release of Immune Growth Hormone (GH) from Chicken Bursal B-Lymphocyte Cultures

2020 ◽  
Vol 21 (4) ◽  
pp. 1436
Author(s):  
Santiago Pech-Pool ◽  
Laura C. Berumen ◽  
Carlos G. Martínez-Moreno ◽  
Guadalupe García-Alcocer ◽  
Martha Carranza ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Mrna Expression ◽  
B Lymphocytes ◽  
Culture Media ◽  
Combined Treatment ◽  
Thyrotropin Releasing Hormone ◽  
Dependent Manner ◽  
Growth Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Intracellular Content

It is known that growth hormone (GH) is expressed in immune cells, where it exerts immunomodulatory effects. However, the mechanisms of expression and release of GH in the immune system remain unclear. We analyzed the effect of growth hormone-releasing hormone (GHRH), thyrotropin-releasing hormone (TRH), ghrelin (GHRL), and somatostatin (SST) upon GH mRNA expression, intracellular and released GH, Ser133-phosphorylation of CREB (pCREBS133), intracellular Ca2+ levels, as well as B-cell activating factor (BAFF) mRNA expression in bursal B-lymphocytes (BBLs) cell cultures since several GH secretagogues, as well as their corresponding receptors (-R), are expressed in B-lymphocytes of several species. The expression of TRH/TRH-R, ghrelin/GHS-R1a, and SST/SST-Rs (Subtypes 1 to 5) was observed in BBLs by RT-PCR and immunocytochemistry (ICC), whereas GHRH/GHRH-R were absent in these cells. We found that TRH treatment significantly increased local GH mRNA expression and CREB phosphorylation. Conversely, SST decreased GH mRNA expression. Additionally, when added together, SST prevented TRH-induced GH mRNA expression, but no changes were observed in pCREBS133 levels. Furthermore, TRH stimulated GH release to the culture media, while SST increased the intracellular content of this hormone. Interestingly, SST inhibited TRH-induced GH release in a dose-dependent manner. The coaddition of TRH and SST decreased the intracellular content of GH. After 10 min. of incubation with either TRH or SST, the intracellular calcium levels significantly decreased, but they were increased at 60 min. However, the combined treatment with both peptides maintained the Ca2+ levels reduced up to 60-min. of incubation. On the other hand, BAFF cytokine mRNA expression was significantly increased by TRH administration. Altogether, our results suggest that TRH and SST are implicated in the regulation of GH expression and release in BBL cultures, which also involve changes in pCREBS133 and intracellular Ca2+ concentration. It is likely that TRH, SST, and GH exert autocrine/paracrine immunomodulatory actions and participate in the maturation of chicken BBLs.

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