Effect of simultaneous administration of GHRH (1–40) and TRH on GH, PRL and TSH secretion in normal man

Giusti, Massimo; Lomeo, A.; Mazzocchi, G.; Torre, R. La; Monachesi, Mario; Sessarego, P; Attanasio, Roberto; Giordano, Giulio

doi:10.1007/bf03346973

Cited by 6 publications

(1 citation statement)

References 29 publications

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“…hypothyroid rats and in many human pathological conditions. However, TRH did not affect GH release in healthy individuals (Giusti et al, 1986). Although TRH has little effect on conscious adult birds, it has been shown to stimulate GH release in immature and anaesthetized birds (Harvey, 1990).…”

Section: Introductionmentioning

confidence: 87%

Expression and Alternative Processing of a Chicken Gene Encoding Both Growth Hormone-Releasing Hormone and Pituitary Adenylate Cyclase-Activating Polypeptide

McRory¹,

Parker²,

Sherwood³

1997

DNA and Cell Biology

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The chicken growth hormone-releasing hormone (GRF) gene was isolated, sequenced, and characterized. In addition, three different mRNAs were isolated from juvenile and adult brain. The first cDNA encoded for a GRF(1-46), the second cDNA encoded for a GRF(1-43) due to a sliding intron boundary, and the third skipped exon four and encoded only GRF(33-46). We also determined that juvenile chicken mRNA encoding GRF is expressed in the brain and gonads, but not in the pituitary, heart, liver, kidney, crop, small intestine, large intestine, eye, and muscle. This gene is also interesting in terms of evolution because another neuropeptide, pituitary adenylate cyclase-activating polypeptide (PACAP), is encoded within the same gene (grf/pacap) in chicken, but on a separate gene (pacap) in mammals. We showed previously that these two neuropeptides were encoded in the same cDNA in fish, but the present evidence in chicken suggests a gene duplication in stem mammals.

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Section: Introductionmentioning

confidence: 87%

Expression and Alternative Processing of a Chicken Gene Encoding Both Growth Hormone-Releasing Hormone and Pituitary Adenylate Cyclase-Activating Polypeptide

McRory¹,

Parker²,

Sherwood³

1997

DNA and Cell Biology

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The effect of GHRH on TSH release in rats in vivo and in vitro

Looij

Kruseman

Roelfsema

et al. 1995

J Endocrinol Invest

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In man, GHRH has been shown to potentiate the TSH-releasing activity of TRH. To study the way by which GHRH affects TRH-stimulated TSH release, we examined the effect of GHRH (1-29)NH2 on basal and stimulated TSH secretion in intact male rats and superfused dispersed rat pituitary cells. In the intact rats, GHRH(1-29)NH2 potentiated TRH-stimulated TSH release in the evening, but potentiation was not observed in the morning and in dispersed pituitary cells. Basal TSH levels were not changed by GHRH(1-29)NH2. It is concluded that GHRH(1-29)NH2 potentiates the TSH-releasing activity of TRH in the evening in rats possibly through suprahypophyseal disinhibition.

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Inhibitory influence of thyrotropin releasing hormone administration on growth hormone response to low doses of growth hormone-releasing hormone in normal man

Zanoboni

Gibillini

Cucchi

et al. 1988

J Endocrinol Invest

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Literature data show that TRH may have either stimulatory or inhibitory actions on GH release according to pathophysiological conditions of the subject. In view of this dual effect of TRH, we studied the possible interaction of TRH and GRF on GH secretion. Six healthy male volunteers received iv in different occasions and in random order: 1) GRF 0.05 micrograms/Kg; 2) GRF 0.1 micrograms/Kg; 3) GRF 1 microgram/Kg; 4) GRF 0.05 micrograms/Kg + TRH 400 micrograms, simultaneously; 5) GRF 0.05 micrograms/Kg + TRH 20 micrograms, simultaneously; 6) GRF 1 microgram/Kg + TRH 400 micrograms, simultaneously, 7) the vehicle as control treatment. Blood samples were obtained at several time intervals and plasma GH, PRL and TSH were measured by RIA methods. Plasma GH significantly increased in all subjects after all the tested doses of GRF and after the combination of the highest and of the lowest doses of GRF + TRH (treatments 6 and 5). GH responses increased progressively with the dose of GRF administered, even if a clear dose-response relationship could not be demonstrated, owing to the considerable interindividual variability in the responsiveness. The administration of GRF 0.05 micrograms/Kg increased significantly plasma GH levels vs control treatment. The simultaneous administration of a low effective dose of GRF (0.05 micrograms/kg) plus a high dose of TRH (400 micrograms) was able to significantly inhibit the GH secretion elicited by GRF 0.05 micrograms/Kg alone. The other GRF + TRH combinations tested (treatments 5 and 6) did not modify the GH response to the same doses of GRF given alone. Plasma PRL and TSH did not change either after GRF at any dose or after the vehicle.(ABSTRACT TRUNCATED AT 250 WORDS)

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Effect of simultaneous administration of GHRH (1–40) and TRH on GH, PRL and TSH secretion in normal man

Cited by 6 publications

References 29 publications

Expression and Alternative Processing of a Chicken Gene Encoding Both Growth Hormone-Releasing Hormone and Pituitary Adenylate Cyclase-Activating Polypeptide

Expression and Alternative Processing of a Chicken Gene Encoding Both Growth Hormone-Releasing Hormone and Pituitary Adenylate Cyclase-Activating Polypeptide

The effect of GHRH on TSH release in rats in vivo and in vitro

Inhibitory influence of thyrotropin releasing hormone administration on growth hormone response to low doses of growth hormone-releasing hormone in normal man

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