The Effect of Thyrotropin-Releasing Hormone (TRH) and Somatostatin (GHRIH) on Growth Hormone and Prolactin Secretion in vitro and in vivo in the Domestic Fowl (Gallus domesticus)

1978 ◽  
Vol 26 (4) ◽  
pp. 249-260 ◽  
Author(s):  
S. Harvey ◽  
C.G. Scanes ◽  
A.C. Chadwick ◽  
N.J. Bolton
Keyword(s):  
Growth Hormone ◽  
Domestic Fowl ◽  
Prolactin Secretion ◽  
Gallus Domesticus ◽  
Thyrotropin Releasing Hormone ◽  
Releasing Hormone

scholarly journals Brain Delivery of Thyrotropin-Releasing Hormone via a Novel Prodrug Approach

Pharmaceutics ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 349 ◽  
Author(s):  
Katalin Prokai-Tatrai ◽  
Daniel L. De La Cruz ◽  
Vien Nguyen ◽  
Benjamin P. Ross ◽  
Istvan Toth ◽  
...  
Keyword(s):  
Brain Homogenate ◽  
Thyrotropin Releasing Hormone ◽  
Metabolic Stability ◽  
Antidepressant Effect ◽  
Brain Delivery ◽  
Small Peptides ◽  
Releasing Hormone ◽  
Membrane Affinity

Using thyrotropin-releasing hormone (TRH) as a model, we explored whether synergistic combination of lipoamino acid(s) and a linker cleaved by prolyl oligopeptidase (POP) can be used as a promoiety for prodrug design for the preferential brain delivery of the peptide. A representative prodrug based on this design principle was synthesized, and its membrane affinity and in vitro metabolic stability, with or without the presence of a POP inhibitor, were studied. The in vivo formation of TRH from the prodrug construct was probed by utilizing the antidepressant effect of the peptide, as well as its ability to increase acetylcholine (ACh) synthesis and release. We found that the prototype prodrug showed excellent membrane affinity and greatly increased metabolic stability in mouse blood and brain homogenate compared to the parent peptide, yet a POP inhibitor completely prevented prodrug metabolism in brain homogenate. In vivo, administration of the prodrug triggered antidepressant-like effect, and microdialysis sampling showed greatly increased ACh release that was also antagonized upon a POP inhibitor treatment. Altogether, the obtained promising exploratory data warrant further investigations on the utility of the prodrug approach introduced here for brain-enhanced delivery of small peptides with neurotherapeutic potential.

A Study of the Effect of the Thyrotropin-Releasing Hormone Metabolite, Histidyl-Proline Diketopiperazine, on Prolactin Secretion in Vivo*

Endocrinology ◽  
1981 ◽  
Vol 109 (5) ◽  
pp. 1375-1379 ◽  
Author(s):  
CHARLES H. EMERSON ◽  
SHARON ALEX ◽  
LEWIS E. BRAVERMAN ◽  
MARJORIE S. SAFRAN
Keyword(s):  
Prolactin Secretion ◽  
Thyrotropin Releasing Hormone ◽  
Releasing Hormone

Effect of synthetic thyrotrophin-releasing hormone and its analogues on growth hormone secretion in the domestic fowl (Gallus Domesticus)

1981 ◽  
Vol 97 (4) ◽  
pp. 448-453 ◽  
Author(s):  
C. G. Scanes ◽  
S. Harvey ◽  
B. A. Morgan ◽  
M. Hayes
Keyword(s):  
Growth Hormone ◽  
Domestic Fowl ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Gallus Domesticus ◽  
Plasma Growth Hormone ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Gh Secretion ◽  
Trh Analogues

Abstract. Variations in plasma growth hormone (GH) concentrations following iv or sc administration of synthetic thyrotrophin-releasing hormone (TRH, Pyr-His-Pro-NH2) have been followed in immature and adult domestic fowl. TRH markedly stimulated GH secretion in newly hatched (1 and 2 day old) chicks and in 6-week-old cockerels but in adult male or female birds of two strains had very little effect, if any. Intravenous injection of 4 TRH analogues (Pyr-His-Mep-NH2, Pyr-Meh-Mep-NH2, Pyr-Meh-Mep-NH and Pyr-Meh-Pro-NH2) were also potent GH secretagogues in 6-week-old birds. The stimulatory effect of TRH or the TRH-analogues on GH secretion was not dose-related.

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