Potent interaction between glucocorticoids and growth hormone-releasing factor in vivo

Science ◽  
1983 ◽  
Vol 221 (4610) ◽  
pp. 556-558 ◽  
Author(s):  
W. Wehrenberg ◽  
A Baird ◽  
N Ling
Keyword(s):  
Growth Hormone ◽  
Growth Hormone Releasing Factor

Periodic interactions of GH-releasing factor and somatostatin can augment GH release in vitro

1987 ◽  
Vol 253 (5) ◽  
pp. E508-E514
Author(s):  
J. Weiss ◽  
M. J. Cronin ◽  
M. O. Thorner
Keyword(s):  
Growth Hormone ◽  
Human Growth Hormone ◽  
Human Growth ◽  
Male Rat ◽  
Base Line ◽  
Additive Effects ◽  
Growth Hormone Releasing Factor ◽  
The Impact

Growth hormone (GH) is secreted as pulses in vivo. To understand the signals governing this periodicity, we have established a perifusion-based model of pulsatile GH release. Male rat anterior pituitaries were dispersed and perifused with pulses of human growth hormone-releasing factor-(1--40) (GHRF), with or without a continuous or discontinuous somatostatin tonus. An experiment was composed of a 1-h base-line collection followed by four 3-h cycles; each contained single or paired 10-min infusion(s) of 3 nM GHRF. In testing the impact of somatostatin, the protocol was identical except that 0.3 nM somatostatin was added 30 min into the base-line period and then was either continued throughout the study or withdrawn during the periods of GHRF infusion. GH base lines with somatostatin were lower than vehicle base lines (P less than 0.05). GHRF pulses generated consistent peaks of GH release between 200 and 300 ng. min-1. (10(7) cells)-1, and these peaks were not altered by continuous somatostatin. In contrast, withdrawal of somatostatin during GHRF administration elicited markedly higher GH peaks (P less than 0.05) and more total GH release (P less than 0.05). This response could not be accounted for by the additive effects of GHRF and somatostatin withdrawal.

In vivo and in vitro evidence of growth hormone-releasing factor-like produced locally in the adenohypophyseal cells of the rat

Neuropeptides ◽  
1991 ◽  
Vol 19 (4) ◽  
pp. 223-229 ◽  
Author(s):  
J. Carretero ◽  
F. Sánchez ◽  
R. Vázquez ◽  
L. Cacicedo ◽  
F. Sánchez-Franco ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Hormone Releasing Factor

In vivo transdermal iontophoretic delivery of growth hormone releasing factor GRF (1–44) in hairless guinea pigs

1992 ◽  
Vol 18 (3) ◽  
pp. 213-220 ◽  
Author(s):  
Saran Kumar ◽  
Hing Char ◽  
Sunil Patel ◽  
David Piemontese ◽  
A.Waseem Malick ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Guinea Pigs ◽  
Growth Hormone Releasing Factor ◽  
Iontophoretic Delivery ◽  
Hairless Guinea Pigs

Ectopic Growth Hormone-Releasing Factor Stimulates Growth Hormone Secretion in the Urethane-Anesthetized Rat in vivo

1983 ◽  
Vol 37 (5) ◽  
pp. 328-331 ◽  
Author(s):  
Marta Szabo ◽  
Daniel Dudlak ◽  
Jennifer L. Thominet ◽  
Lawrence A. Frohman
Keyword(s):  
Growth Hormone ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Growth Hormone Releasing Factor

GROWTH HORMONE-RELEASING FACTOR ANALOGUE (hGRF1-29NH2): IMMUNOREACTIVE-GRF PLASMA LEVELS AFTER INTRAVENOUS AND SUBCUTANEOUS ADMINISTRATION

1985 ◽  
Vol 107 (3) ◽  
pp. R5-R8 ◽  
Author(s):  
B. Rafferty ◽  
S. Poole ◽  
R. Clarke ◽  
D. Schulster
Keyword(s):  
Growth Hormone ◽  
Subcutaneous Administration ◽  
Human Growth ◽  
Large Degree ◽  
Initial Distribution ◽  
Growth Hormone Releasing Factor ◽  
Anaesthetized Rats ◽  
Distribution Phase ◽  
Disappearance Curve

ABSTRACT A homologous radioimmunoassay (RIA) system for human growth hormone-releasing factor 1-29NH2 (hGRF 1-29-NH2) was developed and applied to the measurement of immunoreactive (IR) concentrations of the peptide in anaesthetized rats to determine some of its pharmacokinetics after i.v. and s.c. administration. Analysis of the biphasic disappearance curve of IR-hGRF-1-29NH2 from plasma after i.v. injection (10μg) gave values for the half-lives of the initial distribution phase (α) and for the elimination phase (β) of 1.9 ± 0.2 min and 10.4 ± 0.2 min respectively. There was rapid uptake of the peptide from the site of s.c. injection but comparison of areas under the plasma IR-hGRF1-29NH2/time curves showed that the estimated total amount in the circulation after s.c. injection was only 4% of that obtained after i.v. administration. A large degree of degradation of the peptide is indicated either at the site of injection or during transfer to plasma; this susceptibility to rapid breakdown is reflected in the short half-life of the peptide in the circulation. Therefore the measurement of the above parameters is a prerequisite when assessing potency of GRF analogues in-vivo and when implementing suitable dosage regimens for clinical purposes.

Preliminary Evidence That GnRH Has the Properties of a Growth Hormone-Releasing Factor In Vivo in the Rat

1995 ◽  
Vol 2 (4) ◽  
pp. 623-629 ◽  
Author(s):  
Alan S. Penzias ◽  
Stephanie R. Goodman ◽  
Gabriele Rossi ◽  
Fayek N. Shamma ◽  
Raymond F. Aten ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Preliminary Evidence ◽  
Growth Hormone Releasing Factor
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