Growth hormone-releasing hexapeptide elevates intracellular calcium in rat somatotropes by two mechanisms.

Herrington J, Hille B

Endocrinology1 Sept 1994Cited by 64 (Europe PMC)

PMID8070352DOI10.1210/endo.135.3.8070352PepBankPUB-08070352

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Summary

The text of this summary is not shown here, because the article license does not allow reuse. Read it at the source (opens in a new tab)

Text rights: Publisher copyright. Results still quote short attributed sentences.

Results from this study8

5 results from studies that gave the peptide. No result from this study comes from people.

01LabIn vitro (cells)Mechanism
In rat somatotropes, GHRP‑6 increased intracellular calcium in rapid transient and persistent phases.
In plain wordsIn cells from rats, GHRP‑6 increased internal calcium in two phases.
Peptide
GHRP-6
Outcome
IncreaseIntracellular calcium response
Study
ratn: not reported in source
single somatotropes
Outcome group
Receptor activity and mechanism · Endocrine and hormones
Studied dose
Dose not stated
Source sentences
Summary
GHRP-6 elevated intracellular free Ca2+ ([Ca2+]i) in two phases: a rapid transient phase, followed by a persistent phase.
1 context sentence(design, population, supporting numbers)
Summary · context
The actions of GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 or GHRP-6) on single rat somatotropes were studied using whole cell patch clamp electrophysiology and indo-1 Ca2+ photometry.
Report a problemFND-0807035201
02LabIn vitro (cells)Mechanism
In rat somatotropes, the half-maximal GHRP‑6 concentration for peak calcium release was 49 nM.
In plain wordsIn cells from rats, GHRP‑6 produced half-maximal calcium release at 49 nM.
Peptide
GHRP-6
Outcome
Not applicableHalf-maximal calcium release concentration
Study
ratn: not reported in source
single somatotropes
Outcome group
Receptor activity and mechanism · Endocrine and hormones
Studied dose
Dose not stated
Measurements
Half-maximal concentration
49 nM
peak calcium rise
Source sentences
Summary
The half-maximal concentration for the peak [Ca2+]i rise during Ca2+ release was 49 nM GHRP-6.
1 context sentence(design, population, supporting numbers)
Summary · context
The actions of GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 or GHRP-6) on single rat somatotropes were studied using whole cell patch clamp electrophysiology and indo-1 Ca2+ photometry.
Report a problemFND-0807035203
03LabIn vitro (cells)Mechanism
In rat somatotropes, GHRP‑6-induced calcium release activated voltage-independent calcium-activated potassium conductance.
In plain wordsIn cells from rats, GHRP‑6-induced calcium release activated a potassium current.
Peptide
GHRP-6
Outcome
IncreaseCalcium-activated potassium conductance
Study
ratn: not reported in source
single somatotropes
Outcome group
Receptor activity and mechanism · Endocrine and hormones
Studied dose
Dose not stated
Source sentences
Summary
Simultaneous measurement of [Ca2+]i and membrane current or potential revealed that the transient release of Ca2+ by GHRP-6 activates a voltage-independent Ca(2+)-activated K+ conductance, which transiently hyperpolarizes the somatotrope.
1 context sentence(design, population, supporting numbers)
Summary · context
The actions of GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 or GHRP-6) on single rat somatotropes were studied using whole cell patch clamp electrophysiology and indo-1 Ca2+ photometry.
Report a problemFND-0807035205
04LabIn vitro (cells)Mechanism
In rat somatotropes, GHRP‑6-induced calcium release transiently hyperpolarized the cells.
In plain wordsIn cells from rats, GHRP‑6 briefly made the cell membrane more electrically negative.
Peptide
GHRP-6
Outcome
IncreaseTransient hyperpolarization
Study
ratn: not reported in source
single somatotropes
Outcome group
Receptor activity and mechanism · Endocrine and hormones
Studied dose
Dose not stated
Source sentences
Summary
Simultaneous measurement of [Ca2+]i and membrane current or potential revealed that the transient release of Ca2+ by GHRP-6 activates a voltage-independent Ca(2+)-activated K+ conductance, which transiently hyperpolarizes the somatotrope.
1 context sentence(design, population, supporting numbers)
Summary · context
The actions of GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 or GHRP-6) on single rat somatotropes were studied using whole cell patch clamp electrophysiology and indo-1 Ca2+ photometry.
Report a problemFND-0807035206
05LabIn vitro (cells)Mechanism
In nondialyzed rat somatotropes, GHRP‑6 induced long-lasting depolarization that may explain persistent calcium elevation.
In plain wordsIn cells from rats, GHRP‑6 caused sustained electrical depolarization that may explain the sustained calcium increase.
Peptide
GHRP-6
Outcome
IncreaseLong-lasting depolarization
Study
ratn: not reported in source
single somatotropes
Outcome group
Receptor activity and mechanism · Endocrine and hormones
Studied dose
Dose not stated
Source sentences
Summary
In nondialyzed cells (perforated patch recording), we have identified a long-lasting GHRP-6-induced depolarization which may be responsible for the persistent [Ca2+]i elevation.
1 context sentence(design, population, supporting numbers)
Summary · context
The actions of GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 or GHRP-6) on single rat somatotropes were studied using whole cell patch clamp electrophysiology and indo-1 Ca2+ photometry.
Report a problemFND-0807035208

Studies that did not test the peptide alone3

In this study, GHRP-6 was a lab tool or a carrier, part of a mix, or the subject of a lab method. These results are not evidence about taking GHRP-6.

06LabNot a test of GHRP-6 aloneIn vitro (cells)Mechanism
In rat somatotropes, treatments that blocked calcium entry did not prevent the transient GHRP‑6 calcium response.
In plain wordsIn cells from rats, blocking calcium entry did not prevent the brief GHRP‑6 calcium response.
Peptide
GHRP-6
Outcome
No significant changeTransient calcium response under entry blockade
Study
ratn: not reported in source
single somatotropes
Outcome group
Receptor activity and mechanism · Endocrine and hormones
Source sentences
Summary
Based on its insensitivity to treatments that block Ca2+ entry [removal of external Ca2+, addition of the dihydropyridine Ca2+ channel blocker nitrendipine (1 microM), and the hyperpolarizing action of zero external Na+ or 100 nM somatostatin], the transient elevation is the result of release of Ca2…
1 context sentence(design, population, supporting numbers)
Summary · context
The actions of GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 or GHRP-6) on single rat somatotropes were studied using whole cell patch clamp electrophysiology and indo-1 Ca2+ photometry.
In this study, GHRP-6 was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking GHRP-6.
Report a problemFND-0807035202
07LabNot a test of GHRP-6 aloneIn vitro (cells)Mechanism
In rat somatotropes, caffeine or ryanodine abolished or partly occluded GHRP‑6-induced calcium release.
In plain wordsIn cells from rats, caffeine or ryanodine blocked or partly reduced GHRP‑6-induced calcium release.
Peptide
GHRP-6
Outcome
DecreaseCaffeine or ryanodine blockade
Study
ratn: not reported in source
single somatotropes
Outcome group
Receptor activity and mechanism · Endocrine and hormones
Source sentences
Summary
Prior treatment of cells with caffeine (10 mM) or ryanodine (50 microM) abolished or partially occluded GHRP-6-induced Ca2+ release.
1 context sentence(design, population, supporting numbers)
Summary · context
The actions of GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 or GHRP-6) on single rat somatotropes were studied using whole cell patch clamp electrophysiology and indo-1 Ca2+ photometry.
In this study, GHRP-6 was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking GHRP-6.
Report a problemFND-0807035204
08LabNot a test of GHRP-6 aloneIn vitro (cells)Mechanism
In rat somatotropes, external calcium or sodium removal, nitrendipine, or somatostatin abolished persistent GHRP‑6-induced calcium elevation.
In plain wordsIn cells from rats, ion removal, nitrendipine, or somatostatin stopped the sustained GHRP‑6 calcium increase.
Peptide
GHRP-6
Outcome
DecreasePersistent calcium response blockade
Study
ratn: not reported in source
single somatotropes
Outcome group
Receptor activity and mechanism · Endocrine and hormones
Source sentences
Summary
The GHRP-6-induced persistent [Ca2+]i elevation is abolished by removal of external Ca2+ or external Na+ or the addition of 1 microM nitrendipine or 100 nM somatostatin, consistent with Ca2+ entry through voltage-dependent Ca2+ channels.
1 context sentence(design, population, supporting numbers)
Summary · context
The actions of GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 or GHRP-6) on single rat somatotropes were studied using whole cell patch clamp electrophysiology and indo-1 Ca2+ photometry.
In this study, GHRP-6 was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking GHRP-6.
Report a problemFND-0807035207

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

Version 2Current
21 Oct 2026, 15:58 UTC
Study results updated
Version 1
9 Oct 2026, 03:13 UTC
First added · source update from Europe PMC

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