Stimulation by a TRH precursor, TRH-Gly, of TSH and PRL secretion in rats: effect of starvation.

Abstract

The hypophysial activities of a possible direct precursor of thyrotropin (TSH)-releasing hormone (TRH), TRH-Gly, were evaluated in estrogen, progesterone-primed rats under urethane anesthesia. Intravenous administration of TRH-Gly in doses of 2-200 micrograms caused a significant and dose-dependent increase in blood TSH and prolactin (PRL). The stimulatory activity of TRH-Gly was 170 to 400-times less potent than that of TRH. The lower potency was confirmed by the action of TRH-Gly on the anterior pituitary cells in vitro. In starved rats, TRH-Gly apparently stimulated TSH and PRL secretion in a dose-dependent manner, and the stimulatory activity increased in starved rats as compared to normal controls. TRH-Gly did not affect [3H-MeHis]TRH binding in pituitary plasma membranes. These data imply that large amounts of TRH-Gly may have significant biological activities and these are potentiated in the starved condition.

• Authors: M Mori, M Murakami, T Iriuchijima, K Miyashita, T Satoh, T Monden, T Michimata, I Kobayashi, S Kobayashi
• Journal: Neuropeptides (Neuropeptides) Vol. 16 Issue 2 Pg. 57-62 (Jun 1990) ISSN: 0143-4179 [Print] Netherlands
• PMID: 2123526 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Prodrugs
• Thyrotropin-Releasing Hormone
• Prolactin
• Thyrotropin

Topics

• Animals
• Chromatography, High Pressure Liquid
• Male
• Pituitary Gland, Anterior (cytology, metabolism)
• Prodrugs (pharmacology)
• Prolactin (blood, metabolism)
• Rats
• Rats, Inbred Strains
• Starvation (blood, metabolism)
• Thyrotropin (blood, metabolism)
• Thyrotropin-Releasing Hormone (pharmacology)