Hypothyroidism Reduces Content and Increases in vitro Release of Pro-Thyrotropin-Releasing Hormone Peptides from the Median Eminence

1991 ◽  
Vol 53 (5) ◽  
pp. 511-515 ◽  
Author(s):  
Thomas O. Bruhn ◽  
Joanne H. Taplin ◽  
Ivor M.D. Jackson
Keyword(s):  
Median Eminence ◽  
In Vitro Release ◽  
Thyrotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Vitro Release

Regional distribution of in vitro release of thyrotropin releasing hormone in rat brain

Peptides ◽  
1987 ◽  
Vol 8 (2) ◽  
pp. 291-298 ◽  
Author(s):  
Milagros Mendez ◽  
Patricia Joseph-Bravo ◽  
Miguel Cisneros ◽  
Miguel Angel Vargas ◽  
Jean-Louis Charli
Keyword(s):  
Rat Brain ◽  
Regional Distribution ◽  
In Vitro Release ◽  
Thyrotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Vitro Release

Testosterone regulates the secretion of thyrotrophin-releasing hormone (TRH) and TRH precursor in the rat hypothalamic-pituitary axis

1990 ◽  
Vol 125 (2) ◽  
pp. 263-270 ◽  
Author(s):  
A. E. Pekary ◽  
M. Knoble ◽  
N. H. Garcia ◽  
S. Bhasin ◽  
J. M. Hershman
Keyword(s):  
In Vitro Release ◽  
Serum Levels ◽  
Male Rats ◽  
Testosterone Replacement ◽  
Male Rat ◽  
Posterior Pituitary ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Vitro Release

ABSTRACT Orchidectomy has been reported to decrease concentrations of thyrotrophin (TSH) in the circulation of male rats without affecting serum levels of thyroid hormones. To understand the mechanism underlying this observation, we have measured the effect of gonadal status on the in-vitro release of TSH-releasing hormone (TRH) by male rat hypothalamic fragments. Because hormone release rates can be affected by changes in the post-translational processing of the hormonal precursors, we have also studied the corresponding changes in the concentrations of TRH and TRH-Gly, a TRH precursor peptide in hypothalamus and pituitary, by radioimmunoassay. We observed a significant decline in the in-vitro release of TRH from incubated hypothalami 1 week after castration, which was quantitatively reversed by testosterone replacement. Concentrations of TRH and TRH-Gly in the posterior pituitary, on the other hand, which derive from neurones of hypothalamic origin, increased significantly with castration and were returned to the normal range by testosterone replacement. We conclude that the primary effect of testosterone is the stimulation of hypothalamic TRH release, resulting in the depletion of TRH and TRH precursors from TRH-containing neurones which project into the median eminence and posterior pituitary. Journal of Endocrinology (1990) 125, 263–270

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