Oral activity of the growth hormone releasing peptide His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 in rats, dogs and monkeys

Walker, Richard F.; Codd, Ellen E.; Barone, Frank C.; Nelson, Allen H.; Goodwin, T. Murphy; Campbell, Sarah

doi:10.1016/0024-3205(90)90563-7

Cited by 87 publications

(35 citation statements)

References 12 publications

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“…These observations are compatible with findings in humans, showing that not only the GH-releasing effect of ghrelin (Broglio et al, 2003) but also that of GHRH and peptidyl or non-peptidyl synthetic GHSs undergoes an age-related decrease (Aloi et al, 1994;Bowers et al, 1992;Broglio et al, 2003;Chapman et al, 1996;Muccioli et al, 2002). In old rats, the GH response to synthetic GHSs is impaired as well (Ceda et al, 1986;Walker et al, 1990). Also in old dogs, the GH responsiveness to the synthetic GHS hexarelin has been reported to be low (Cella et al, 1995).…”

Section: Discussionsupporting

confidence: 85%

“…GHRH, despite the availability of a remarkable GHreleasable pool (Giustina and Veldhuis, 1998;Ghigo et al, 1999;Muccioli et al, 2002). These observations support the idea that the somatopause is driven primarily by the hypothalamus and that the pituitary somatotropes retain their capacity to synthesise and secrete adequate levels of GH (Cella et al, 1993;Corpas et al, 1992;Franchimont et al, 1989;Muccioli et al, 2002;Muller et al, 1999;Walker et al, 1990).…”

Section: Discussionmentioning

confidence: 84%

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Effects of growth hormone secretagogues on the release of adenohypophyseal hormones in young and old healthy dogs

Bhatti

Duchateau

Ham

et al. 2006

The Veterinary Journal

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The effects of three growth hormone secretagogues (GHSs), ghrelin, growth hormone-releasing peptide-6 (GHRP-6), and growth hormone-releasing hormone (GHRH), on the release of adenohypophyseal hormones, growth hormone (GH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), luteinising hormone (LH), prolactin (PRL) and on cortisol were investigated in young and old healthy Beagle dogs.Ghrelin proved to be the most potent GHS in young dogs, whereas in old dogs GHRH administration was associated with the highest plasma GH concentrations. The mean plasma GH response after administration of ghrelin was significantly lower in the old dogs compared with the young dogs. The mean plasma GH concentration after GHRH and GHRP-6 administration was lower in the old dogs compared with the young dogs, but this difference did not reach statistical significance. In both age groups, the GHSs were specific for GH release as they did not cause significant elevations in the plasma concentrations of ACTH, cortisol, TSH, LH, and PRL. It is concluded that in young dogs, ghrelin is a more powerful stimulator of GH release than either GHRH or GHRP-6. Ageing is associated with a decrease in GH-releasing capacity of ghrelin, whereas this decline is considerably lower for GHRH or GHRP-6.

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Section: Discussionsupporting

confidence: 85%

Section: Discussionmentioning

confidence: 84%

Effects of growth hormone secretagogues on the release of adenohypophyseal hormones in young and old healthy dogs

Bhatti

Duchateau

Ham

et al. 2006

The Veterinary Journal

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“…The activity of GHRP in releasing GH was observed when administered directly into the gastrointestinal tract in rats, dogs and monkeys [27]. In man, GHRP infusion resulted in a selective and dose-dependent increase in serum GH concentrations [28].…”

Section: Discussionmentioning

confidence: 97%

Effect of Growth Hormone (GH)-Releasing Peptide (GHRP) on the Release of GH from Cultured Anterior Pituitary Cells in Cattle.

1994

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“…The [20]; however, no correction was made for the molar ratio. In monkeys, orally administered GHRP was reported to be 5-20 times more effective than in rats or dogs [43].…”

Section: Introductionmentioning

confidence: 99%

“…GHRP also stimulates release of GH in rat, primate, chick, porcine, ovine and bovine species [8,10,19,20,31]. Furthermore the peptide is efficient if orally administered in rats, dogs and monkeys [43], and in man [14,27]; however, its effect is about 300-fold less potent than when administered i.v.…”

Section: Introductionmentioning

confidence: 99%

In vivo effects of the GH-releasing heptapeptide GHRP-1 in lambs

Charrier¹,

Fraysse²,

Guilhermet³

et al. 1998

Reprod. Nutr. Dev.

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-The novel synthetic growth hormone-releasing heptapeptide GHRP-is reported to be more potent than growth hormone-releasing hormone (GHRH) in eliciting GH release in vivo in rats and man. However, in ovine pituitary cells in primary culture in a perifusion system, GHRP-1 was 10-fold less active than GHRH. The purpose of this work was to study the effect of GHRP-1 in sheep in vivo. Ovine GH release stimulated by either GHRP-1 or GHRH() -29)NH!, in eight pre-ruminant lambs, was determined. GHRP-was administered at doses of 1.2, 2.4 and 6 nmole/kg by i.v. bolus, and GHRH(1-29)NH! at 0.3 nmole/kg. Mean ± s.e.m. peak GH levels in the plasma after injection of saline, 1.2, 2.4, 6 nmole/kg GHRP-and 0.3 nmole/kg GHRH were 2.2 ± 0.9, 9.3 ± 2.5, 8.8 ± 2.4, 35.1 ± 5.8 and 5 I .6 ± 10.5 ng/mL, respectively. As spontaneous 20 ng/mL peaks were observed, only peaks above this level can be considered as significant. The highest dose of GHRP-1 (6 nmole/kg) elicited oGH release, but its action was surpassed by GHRH 0.3 nmole/kg. Furthermore GHRP-1 and GHRH appear to behave inversely when response amplitudes are considered. Animals exhibiting a strong reaction to GHRH-1, show a correspondingly weak reaction to GHRH and vice-versa

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Oral activity of the growth hormone releasing peptide His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 in rats, dogs and monkeys

Cited by 87 publications

References 12 publications

Effects of growth hormone secretagogues on the release of adenohypophyseal hormones in young and old healthy dogs

Effects of growth hormone secretagogues on the release of adenohypophyseal hormones in young and old healthy dogs

Effect of Growth Hormone (GH)-Releasing Peptide (GHRP) on the Release of GH from Cultured Anterior Pituitary Cells in Cattle.

In vivo effects of the GH-releasing heptapeptide GHRP-1 in lambs

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