The interaction of growth hormone releasing hormone with other hypothalamic hormones on the release of anterior pituitary hormones.
To determine whether the 29 amino-acid fragment of growth hormone releasing hormone (GHRH) can be combined with other hypothalamic releasing hormones in a single test of anterior pituitary reserve, the responses of anterior pituitary hormones to combinations of an i.v. bolus of GHRH(1-29)NH2 or saline with an i.v. bolus of either LH releasing hormone (LHRH) plus TRH, ovine CRH(oCRH) or saline were studied. Each infusion of GHRH(1-29)NH2 resulted in a rapid increment of the plasma GH value. Infusion of GHRH(1-29)NH2 also caused a small and transient rise in plasma PRL, but no change in the integrated PRL response. The combination of GHRH(1-29)NH2 with LHRH plus TRH caused a larger increment of peak and integrated plasma TSH levels than LHRH plus TRH alone. GHRH(1-29)NH2 did not affect the release of other anterior pituitary hormones after infusion with oCRH or LHRH plus TRH. Because of the finding of potentiation of the TSH-releasing activity of LHRH plus TRH by GHRH(1-29)NH2, the study was extended to the investigation of TSH release after infusion of TRH in combination with either GHRH(1-29)NH2 or GHRH(1-40). In this study the combination of TRH with both GHRH preparations also caused a larger increment of the peak and integrated plasma TSH levels than TRH alone. It is concluded that GHRH(1-29)NH2 possesses moderate PRL-releasing activity apart from GH-releasing activity. In addition, GHRH potentiates the TSH-releasing activity of TRH.(ABSTRACT TRUNCATED AT 250 WORDS)
Looij
B J
BJ
Nieuwenhuijzen Kruseman
A C
AC
Mudde
A H
AH
Frölich
M
M
Piaditis
G P
GP
Hodgkinson
S C
SC
McLean
C
C
Grossman
A
A
Coy
D H
DH
Rees
L H
LH
D000328:Adult; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D004347:Drug Interactions; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D013006:Growth Hormone / Q000378:metabolism; D013007:Growth Hormone-Releasing Hormone / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology; D010901:Pituitary Function Tests; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D010906:Pituitary Hormone-Releasing Hormones / Q000494:pharmacology*; D010908:Pituitary Hormones, Anterior / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism; D017337:Sermorelin; D013972:Thyrotropin / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology
D010446:Peptide Fragments; D010906:Pituitary Hormone-Releasing Hormones; D010908:Pituitary Hormones, Anterior; C036893:somatotropin releasing factor 40; D007987:Gonadotropin-Releasing Hormone; D013973:Thyrotropin-Releasing Hormone; D017337:Sermorelin; D011388:Prolactin; D007986:Luteinizing Hormone; D013972:Thyrotropin; D013006:Growth Hormone; D003346:Corticotropin-Releasing Hormone; D013007:Growth Hormone-Releasing Hormone