Growth hormone (GH) responsiveness to GHRH in normal adults is not affected by short-term gonadal blockade

1989 ◽  
Vol 120 (1) ◽  
pp. 31-36 ◽  
Author(s):  
L. Lima ◽  
V. Arce ◽  
N. Lois ◽  
C. Fraga ◽  
M.J. Lechuga ◽  
...  
Keyword(s):  
Gh Deficiency ◽  
Gonadal Steroids ◽  
Receptor Blockade ◽  
Testosterone Enanthate ◽  
Short Term ◽  
Gh Secretion ◽  
Before And After ◽  
Normal Men ◽  
Ghrh Test ◽  
Normal Adults

Abstract. The effects of changes in circulating gonadal steroids on GH secretion elicited by GHRH challenge (1 μg/kg) in normal adults volunteers (aged 18–24 years), were evaluated in 10 women and 10 men before and after gonadal blockade was achieved by a GnRH agonist (1500 μg/day by nasal spray for 40 days). To see if the effect of testosterone on GH secretion was dependent on its aromatization to estradiol (E2), GHRH tests were performed in 7 normal men prior to administration of testosterone enanthate (250 mg im), 8 days after this treatment had began, and again after E2 receptor blockade with tamoxifen (30 mg for 2 days plus 10 mg on the third day 2 h before the GHRH test, po) administered 8 days after testosterone enanthate. The study of the functional status of the somatotropes at the time of GHRH testing was made according to our previous postulate. Short-term gonadal blockade did not affect the parameters of GH response to GHRH in neither women nor men. Thus, the functional blockade of the gonads may be advisable as an adjunct therapy in the treatment of hypothalamic GH-deficiency during the peripubertal stage. In the other group of men, administration of testosterone enanthate significantly increased GHRH-elicited GH release, but this was reverted after E2 receptor blockade. Since the hypothalamic-somatotrope rhythm was altered by both these farmacological manipulations, it appears that testosterone acts on GH release mainly at the suprapituitary level, and that this action is secondary to its aromatization to E2

scholarly journals Effect of one month ketoconazole treatment on GH, cortisol and ACTH release after ghrelin, GHRP-6 and GHRH administration in patients with cushing’s disease

2007 ◽  
Vol 51 (7) ◽  
pp. 1110-1117 ◽  
Author(s):  
Silvia R. Correa-Silva ◽  
Sérgio O. Nascif ◽  
Marcos R. Silva ◽  
Patrícia Molica ◽  
Ana-Maria J. Lengyel
Keyword(s):  
Cushing’S Disease ◽  
Pituitary Function ◽  
Cushing's Disease ◽  
Urinary Cortisol ◽  
Short Term ◽  
Gh Secretion ◽  
Before And After ◽  
Cortisol Responses ◽  
Cortisol Levels ◽  
Acth Release

GH responses to ghrelin, GHRP-6, and GHRH in Cushing’s disease (CD) are markedly blunted. There is no data about the effect of reduction of cortisol levels with steroidogenesis inhibitors, like ketoconazole, on GH secretion in CD. ACTH levels during ketoconazole treatment are controversial. The aims of this study were to compare the GH response to ghrelin, GHRP-6, and GHRH, and the ACTH and cortisol responses to ghrelin and GHRP-6 before and after one month of ketoconazole treatment in 6 untreated patients with CD. Before treatment peak GH (mg/L; mean ± SEM) after ghrelin, GHRP-6, and GHRH administration was 10.0 ± 4.5; 3.8 ± 1.6, and 0.6 ± 0.2, respectively. After one month of ketoconazole there was a significant decrease in urinary cortisol values (mean reduction: 75%), but GH responses did not change (7.0 ± 2.0; 3.1 ± 0.8; 0.9 ± 0.2, respectively). After treatment, there was a significant reduction in cortisol (mg/dL) responses to ghrelin (before: 30.6 ± 5.2; after: 24.2 ± 5.1). No significant changes in ACTH (pg/mL) responses before (ghrelin: 210.9 ± 69.9; GHRP-6: 199.8 ± 88.8) and after treatment (ghrelin: 159.7 ± 40.3; GHRP-6: 227 ± 127.2) were observed. In conclusion, after short-term ketoconazole treatment there are no changes in GH or ACTH responses, despite a major decrease of cortisol levels. A longer period of treatment might be necessary for the recovery of pituitary function.

Cholinergic modulation of GH secretion in acromegalic patients before and after pituitary surgery

1992 ◽  
Vol 127 (6) ◽  
pp. 489-493 ◽  
Author(s):  
Leon Fiszlejder ◽  
Olga Penacini ◽  
Susana Ratz ◽  
Adriana Oneto ◽  
Maria Storani ◽  
...  
Keyword(s):  
Area Under The Curve ◽  
Pituitary Surgery ◽  
Normal Subjects ◽  
Physiological Control ◽  
Gh Secretion ◽  
Pathophysiological Role ◽  
Before And After ◽  
Transsphenoidal Adenomectomy ◽  
Ghrh Test

Cholinergic neurotransmission exerts a physiological control on GH secretion. Pirenzepine (Pz), an antagonist of muscarinic receptors, by enhancing hypothalamic somatostatin release, inhibits stimulated GH secretion in normal subjects but not in acromegalic patients. To address the hypothesis that a feedback effect of GH hypersecretion can be involved in this condition, GH responses to GHRH 1–29, 1 μg/kg iv, with and without administration of Pz, 40mg iv before tests, were investigated in eight acromegalic patients, before and 20–30 days after transsphenoidal adenomectomy. Pz diminished (p<0.001) the incremental area under the curve (AUC) of GH responses to GHRH in seven normal controls. In contrast, GHRH responsiveness in untreated acromegalic patients was not affected by Pz. Postoperative basal GH levels decreased by 62.4±14.9% (p<0.01). Pz inhibited GH responses to GHRH (p<0.01). Furthermore, a direct relationship (r = 0.73, p<0.01) between basal concentrations and the AUC of GH responses following Pz plus GHRH-test was found. The finding that muscarinic receptor activity recovered after the reduction of serum GH basal levels by pituitary surgery lends support to the proposed pathophysiological role of GH excess as a possible determinant factor in cholinergicsomatostatinergic dysfunction in acromegaly.

scholarly journals Integrity of the Growth Hormone/Insulin-Like Growth Factor System Is Maintained in Patients with Chronic Fatigue Syndrome1

2000 ◽  
Vol 85 (4) ◽  
pp. 1433-1439
Author(s):  
Anthony J. Cleare ◽  
Samantha S. Sookdeo ◽  
Jennifer Jones ◽  
Veronica O’Keane ◽  
John P. Miell
Keyword(s):  
Growth Factor ◽  
Gh Deficiency ◽  
Serum Insulin ◽  
Stress Test ◽  
Chronic Fatigue ◽  
Insulin Like Growth Factor ◽  
Fatigue Syndrome ◽  
Before And After ◽  
Ghrh Test ◽  
Hydrocortisone Treatment

GH deficiency states and chronic fatigue syndrome (CFS) share several characteristics, and preliminary studies have revealed aspects of GH dysfunction in CFS. This study assessed indexes of GH function in 37 medication-free CFS patients without comorbid psychiatric illness and 37 matched healthy controls. We also assessed GH function before and after treatment with low dose hydrocortisone, which has been shown recently to reduce fatigue in CFS. We measured basal levels of serum insulin-like growth factor I (IGF-I), IGF-II, IGF-binding protein-1 (IGFBP-1), IGFBP-2 and IGFBP-3 together with 24-h urinary GH excretion. We also performed 2 dynamic tests of GH function: a 100-μg GHRH test and an insulin stress test using 0.15 U/kg BW insulin. There were no differences between patients and controls in basal levels of IGF/IGFBP or in urinary GH excretion. GH responses to both the GHRH test and the insulin stress test were no different in patients and controls. CFS patients did have a marginally reduced suppression of IGFBP-1 during the insulin stress test. Hydrocortisone treatment had no significant effect on any of these parameters. There is no evidence of GH deficiency in CFS. At the doses used, hydrocortisone treatment appears to have little impact on GH function.

scholarly journals Comparison between Insulin-Induced Hypoglycemia and Growth Hormone (GH)-Releasing Hormone + Arginine as Provocative Tests for the Diagnosis of GH Deficiency in Adults1

1998 ◽  
Vol 83 (5) ◽  
pp. 1615-1618 ◽  
Author(s):  
G. Aimaretti ◽  
G. Corneli ◽  
P. Razzore ◽  
S. Bellone ◽  
C. Baffoni ◽  
...  
Keyword(s):  
Gh Deficiency ◽  
Clinical Context ◽  
Provocative Test ◽  
Female Age ◽  
Gh Secretion ◽  
The Third ◽  
Independent Test ◽  
The Mean ◽  
Normal Adults ◽  
Similar Peak

There is now wide consensus that, within an appropriate clinical context, GH deficiency (GHD) in adults must be shown biochemically by provocative testing of GH secretion and that appropriate cut-off limits have to be defined for each provocative test. Insulin-induced hypoglycemia (ITT) is indicated as the test of choice, and severe GHD, to be treated with recombinant human GH replacement, is defined by a GH peak response to ITT of less than 3 μg/L. GHRH + arginine (GHRH+ARG) is one of the most promising tests in alternative to ITT. In fact, it has been reported as a potent, reproducible, and age-independent test and that it is able to distinguish between GHD and normal adults. The aim of the present study was to compare the GH response to ITT and GHRH+ARG in a large group of hypopituitary adults (n = 40; 29 male and 11 female; age: 36.4 ± 2.1 yr). The third centile limit of the peak GH response to ITT has been reported as 5 μg/L, whereas in our lab, that to GHRH+ARG is 16.5 μg/L. In hypopituitary adults, the mean peak GH response to ITT (1.5 ± 0.2 μg/L, range: 0.1–8.5μ g/L) was lower (P &lt; 0.001) than that to GHRH+ARG (3.0 ± 0.4 μg/L, range 0.1–12.0 μg/L), though there was positive correlation (r = 0.61, P &lt; 0.001) between the GH responses to the 2 tests. The peak GH response to GHRH+ARG, but not that to ITT, was positively (though weakly) associated with insulin-like growth factor-I levels (r = 0.35, P &lt; 0.03). Childhood and adult onset GHD patients, as well as patients with single and multiple pituitary insufficiencies, had similar peak GH responses to ITT or GHRH+ARG. Analyzing individual GH responses, 4/40 (10%) of the hypopituitary patients had GH peaks higher than 5 μg/L after ITT; moreover, 3 other patients (7%) had GH peaks, after ITT, higher than 3 μg/L. On the other hand, after GHRH+ARG, all patients had GH peaks lower than 16.5 μg/L, whereas 21/40 (52.5%) had GH peaks higher than 3 μg/L. Because 3 μg/L is the arbitrary cut-off for ITT, the third centile limit of which is 5μ g/L, we arbitrarily considered 9 μg/L as the cut-off point for GHRH+ARG. It is noteworthy that 37/40 (92.5%) patients had a GH peak,. after GHRH+ARG, below this limit. In conclusion, our present results confirm that the ITT test is a reliable provocative test for the diagnosis of adult GHD, whereas they show that the GHRH+ARG test is, at least, as sensitive as the ITT test (provided that appropriate cut-off limits are considered). Note that even the arbitrary cut-off point below which severe GHD is demonstrated has to be appropriate to the potency of the test.

Influence of chronic naltrexone treatment on growth hormone secretion in normal subjects

1997 ◽  
pp. 631-634 ◽  
Author(s):  
P Villa ◽  
D Valle ◽  
L De Marinis ◽  
A Mancini ◽  
A Bianchi ◽  
...  
Keyword(s):  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Normal Subjects ◽  
Molar Ratio ◽  
Normal Female ◽  
Gh Secretion ◽  
Igf I ◽  
Before And After ◽  
Ghrh Test ◽  
Igfbp 3

OBJECTIVE: To verify if a chronic opioid blockade could affect the GH/IGF-I axis. DESIGN: We have investigated the effects of naltrexone (NTX) treatment on GH response to GHRH in normal women. METHODS: GHRH test (50 micrograms i.v.) performed in seven normal female volunteers (age 25-38 years, with a body mass index ranging from 19.8 to 23.1 kg/m2) before and after 4-weeks NTX treatment (50 mg p.o. daily). RESULTS: Basal GH, IGF-I, insulin-like growth factor binding protein-3 (IGFBP-3) plasma levels and the IGF-I/IGFBP-3 molar ratio remained unaffected by NTX. NTX significantly reduced the GH peak values (15.52 +/- 3.59 vs 4.78 +/- 0.49 micrograms/l; P < 0.01), and GH area under curve (918.93 +/- 253.96 vs 401.09 +/- 79.63 micrograms/l; P < 0.01). CONCLUSIONS: This finding suggests that the long-term opioid receptor blockade has an inhibitory role on GHRH-induced GH secretion. A central influence on neurotransmitter control of GH might be hypothesised. The inhibition of stimulated GH release, without interference with the basal level, could indicate an enhanced somatostatin secretion and/or activity. Opioids could be involved only in the regulation of GH dynamics and not in basal secretion. Nevertheless, a direct involvement of opioids at the pituitary level, which could be modified by NTX, cannot be excluded.

scholarly journals Diagnosis of growth hormone deficiency in adults by testing with GHRP-6 alone or in combination with GHRH: comparison with the insulin tolerance test

2002 ◽  
pp. 667-672 ◽  
Author(s):  
S Petersenn ◽  
R Jung ◽  
FU Beil
Keyword(s):  
Growth Hormone ◽  
Gh Deficiency ◽  
Group Versus ◽  
Tolerance Test ◽  
Insulin Tolerance Test ◽  
Hormone Deficiency ◽  
Peak Response ◽  
Gh Secretion ◽  
Insulin Tolerance ◽  
Ghrh Test

OBJECTIVE: The diagnosis of GH deficiency in adults should be made using provocative testing of GH secretion. The insulin tolerance test (ITT) is recommended as the gold standard investigation. Because of the risk of serious complications, patients with epilepsy or known ischemic heart disease should not undergo this test. GHRP-6 is a synthetic hexapeptide that releases GH by binding to specific hypothalamic and pituitary receptors. We assessed the diagnostic capability of GH stimulation by GHRP-6 alone or in combination with GHRH in comparison to the results of an ITT. DESIGN: Twenty patients underwent an ITT for suspected pituitary or adrenal disease. Either GHRP-6 (1 microg/kg) alone, or GHRP-6 in combination with GHRH (1 microg/kg) were administered on different days. Blood samples were obtained during a subsequent 90-min period for measurement of GH. RESULTS: Ten patients had a GH peak response of less than 3 microg/l during ITT and were considered growth hormone deficient (GHD). The GH mean peak (+/-S.E.M., range) in this group was 0.7 microg/l (+/-0.3, 0.1-2.9) compared with 14.5 microg/l (+/-3.5, 3.8-40.8) in the group of patients with a GH peak response of more than 3 microg/l (growth hormone sufficient (GS)). For the GHRP-6 test, the GH mean peak was 1.3 microg/l (+/-0.6, 0.1-6.7) in the GHD group versus 25.7 microg/l (+/-5.5, 7.7-54.2) in the GS group. After GHRP-6+GHRH, the GH mean peaks were 4.0 microg/l (+/-1.3, 0.2-11.9) versus 54.7 microg/l (+/-11.1, 13.9-136.0) respectively. During administration of GHRP-6, the only side effects observed were flush symptoms. CONCLUSIONS: Peak GH levels below 7 microg/l for the GHRP-6 test and below 13 microg/l for the combined GHRP-6+GHRH test identified all patients with GH deficiency correctly as defined by ITT. The results suggest that testing with GHRP-6 or GHRP-6+GHRH is as sensitive and specific as an ITT for the diagnosis of adult GH deficiency.

Measurement of nocturnal urinary growth hormone values

1989 ◽  
Vol 121 (2) ◽  
pp. 290-296 ◽  
Author(s):  
Izumi Sukegawa ◽  
Naomi Hizuka ◽  
Kazue Takano ◽  
Kumiko Asakawa ◽  
Reiko Horikawa ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Gh Deficiency ◽  
Turner's Syndrome ◽  
Turner’S Syndrome ◽  
Gh Secretion ◽  
Short Children ◽  
The Mean ◽  
Plasma Gh ◽  
Normal Adults ◽  
Collection Time

Abstract. Nocturnal urinary growth hormone values were measured by a sensitive enzyme immunoassay in normal adults, patients with GH deficiency, patients with Turner's syndrome, normal but short children who had normal plasma GH responses to provocative tests, and patients with acromegaly. The mean nocturnal urinary GH values in patients with acromegaly were significantly greater than those in normal adults (1582.3 ± 579.8 vs 53.5 ± 8.6 pmol/mmol creatinine (± sem); p < 0.05). In the normal but short children and patients with Turner's syndrome, the mean nocturnal urinary GH values were 83.1 ± 5.2 and 79.8 ± 29.5 pmol/mmol creatinine, respectively. In patients with GH deficiency, the nocturnal urinary GH values were undetectable (< 5.3 pmol/mmol creatinine) except in one patient where the value was 6.3 pmol/mmol creatinine. The nocturnal urinary GH values of the patients with GH deficiency were significantly lower than those of the other groups (p < 0.05). In normal but short children, the nocturnal urinary GH values correlated significantly with mean plasma nocturnal GH concentrations (r = 0.76, p < 0.001), and 24-hour urinary GH values (r = 0.84, p < 0.001), respectively. In 4 patients with GH deficiency who had circulating anti-hGH antibody, the urinary GH values were also undectable. These data indicate that nocturnal urinary GH value reflects endogenous GH secretion during collection time, and that measurement of the nocturnal urinary GH values is a useful method for screening of patients with GH deficiency and acromegaly.

scholarly journals The Impact of Short-Term Fasting on the Dynamics of 24-Hour Growth Hormone (GH) Secretion in Patients with Severe Radiation-Induced GH Deficiency

2006 ◽  
Vol 91 (3) ◽  
pp. 987-994 ◽  
Author(s):  
Ken H. Darzy ◽  
Robert D. Murray ◽  
Helena K. Gleeson ◽  
Suzan S. Pezzoli ◽  
Michael O. Thorner ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Gh Deficiency ◽  
Short Term ◽  
Gh Secretion ◽  
Radiation Induced ◽  
The Impact
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