Effect of D-Ala-D-beta Nal-Ala-Trp-D-Phe-Lys-NH2 (KP-102) on GH secretion in urethan-anesthetized rats.
The effect of a newly developed growth hormone (GH)-releasing hexapeptide (KP-102) on GH secretion was studied in urethan-anesthetized adult male rats. Although KP-102 alone exerted a small influence on GH secretion, it produced a large plasma GH response in the presence of exogenous GH-releasing factor (GRF). During the continuous infusion of GRF, the somatotropes became refractory to a large bolus dose of GRF, but KP-102 induced a marked increase of plasma GH. The GH response to KP-102 alone or KP-102 with GRF was significantly augmented when antiserum to somatostatin (ASS) was previously administered. Although KP-102 and GRF acted synergistically on GH secretion in control animals, they acted additively in ASS-administered rats. The KP-102 effect on plasma GH was significantly attenuated in control animals and ASS-administered rats by prior i.v. injection of antiserum to GRF. Taken together, KP-102 stimulates GH secretion dependent on GRF and appears to act synergistically with GRF by antagonizing the SS effect.
Department of Medicine, Nippon Medical School, Tokyo, Japan.
H
H
Sawada
H
H
Sugihara
H
H
Onose
S
S
Minami
T
T
Shibasaki
I
I
Wakabayashi
D000818:Animals; D004305:Dose-Response Relationship, Drug; D013006:Growth Hormone / Q000097:blood / Q000276:immunology / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014520:Urethane
D007106:Immune Sera; D009842:Oligopeptides; D014520:Urethane; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; C091874:growth hormone-releasing peptide-2