DYNAMIC EVALUATION OF GROWTH HORMONE (GH) AND PROLACTIN (hPRL) SECRETION IN ACTIVE ACROMEGALY WITH HIGH AND LOW GH OUTPUT

1975 ◽  
Vol 78 (2) ◽  
pp. 251-257 ◽  
Author(s):  
G. Tolis ◽  
L. Kovacs ◽  
H. Friesen ◽  
J. B. Martin

ABSTRACT Ten patients with active acromegaly were studied. In 9 plasma GH levels failed to suppress after glucose (OGTT), in 8 an increase in serum GH occurred after thyrotrophin releasing hormone (TRH). After L-Dopa, 4 patients showed no change in serum GH, 3 exhibited a decrease and in 3 an increase in serum hGH occurred. With a combined insulin (ITT) and arginine (ATT) test, 2 patients exhibited an increase in hGH, and in 6 no change occurred. Fasting serum GH concentration was less than 11 ng/ml in 5 patients. Basal prolactin (hPRL) levels were normal in all patients including two with galactorrhea. L-Dopa suppressed and TRH stimulated hPRL secretion in all, but the responses which were seen were subnormal. Hydrocortisone infusion in two acromegalics did not affect the prolactin induced increase after TRH but blunted the GH increase after TRH.

1982 ◽  
Vol 99 (3) ◽  
pp. 344-351 ◽  
Author(s):  
Abraham Martinez-Campos ◽  
Paolo Giovannini ◽  
Antonello Novelli ◽  
Daniela Cocchi ◽  
Tommaso Caraceni ◽  
...  

Abstract. The thyrotrophin (TSH) and prolactin (Prl)-releasing effects of TSH-releasing hormone (TRH) were investigated in 20 subjects with Parkinson's disease (PD), unmedicated, on chronic treatment with a combination levodopa-benserazide (Madopar) or levodopa-carbidopa (Sinemet) or withdrawn from therapy. Administration of TRH (200 μg iv) induced in unmedicated patients TSH and Prl responses significantly lower than those of sex-and age-matched controls. In patients on Madopar therapy the TSH and Prl responses to TRH were greater than in unmedicated patients and comparable to those of controls, while in patients on Sinemet therapy the pituitary responses were undistinguishable from those of unmedicated subjects. Withdrawal of Madopar therapy resulted in a marked diminution of the TSH response but did not affect the Prl response to TRH. Withdrawal of Sinemet therapy did not alter the TSH and Prl responses to TRH. Concomitant evaluation of growth hormone (GH) levels, in none of the subjects evidenced non-specific changes in plasma GH following TRH. Since TSH and Prl responses to TRH are inhibited by an enhancement of the dopaminergic tone, it would appear that the latter is preserved in the tuberoinfundibular system of unmedicated subjects and subjects on chronic Sinemet therapy, but is defective in subjects on chronic Madopar therapy.


1988 ◽  
Vol 118 (2) ◽  
pp. 233-236 ◽  
Author(s):  
E. R. Kühn ◽  
A. Vanderpooten ◽  
L. M. Huybrechts ◽  
E. Decuypere ◽  
V. Darras ◽  
...  

ABSTRACT Plasma GH, tri-iodothyronine (T3), thyroxine (T4) and liver 5′-monodeiodination (5′-D) activity were measured in 18-day-old chick embryos injected with thyrotrophin-releasing hormone (TRH) and human pancreatic growth hormone releasing factor (hpGRF). Injections of 0·1 and 1 μg TRH and 1·5 μg hpGRF increased the concentration of plasma GH while injection of 15 μg hpGRF had no effect. Concentrations of plasma T3 were raised after injection of TRH or hpGRF. Injections of TRH but not of hpGRF raised the concentration of plasma T4. The increases in concentration of plasma T3 after injection of TRH or hpGRF were parallelled by increases in liver 5′-D activity. An injection of 0·25 μg T4 significantly raised the concentration of T4 in plasma but had no effect on plasma T3 or liver 5′-D activity. It is concluded that the release of chicken GH by TRH or hpGRF is responsible for the observed increases in plasma concentration of T3 and liver 5′-D activity. J. Endocr. (1988) 118, 233–236


1994 ◽  
Vol 140 (3) ◽  
pp. 495-502 ◽  
Author(s):  
T P Fletcher ◽  
I J Clarke

Abstract This study examined the effect of thyroidectomy (TX) on the GH axis in sheep. The secretion of GH was monitored 10 and 77 days after TX or sham-TX when the effects on plasma GH and prolactin levels of the injection of 0·5 μg GH-releasing factor (GRF)/kg and 1 μg thyrotrophin-releasing hormone (TRH)/kg were also assessed. There were no significant differences in GH pulse amplitude, pulse frequency, inter-pulse interval and GH secreted/h between sham-TX and TX animals at 10 or 77 days after TX. There was no difference in the GH response to GRF injection in sham-TX sheep at any time but in TX sheep the GH response was significantly (P<0·05) attenuated 10 days after TX. After 77 days the GH response was similar to the response before TX. There was no measurable GH response to injection of TRH in sham-operated or TX sheep at any time. The prolactin response to TRH was not affected by TX or sham-TX. These results suggest that TX in sheep does not affect GH secretion but paradoxically the response to GRF is attenuated in hypothyroid sheep in the short term. TRH causes release of prolactin but not GH in sheep. Journal of Endocrinology (1994) 140, 495–502


1991 ◽  
Vol 125 (5) ◽  
pp. 487-490 ◽  
Author(s):  
Hajime Watanobe ◽  
Shinsuke Sasaki ◽  
Kazuo Takebe

Abstract. We re-examined whether CRH stimulates GH secretion in acromegaly. Human CRH (100 μg) was given as an iv bolus to 15 patients with active acromegaly, and plasma GH levels were measured before and at intervals up to 120 min after the injection. For comparison, we assessed in all the patients the effects of TRH (500 μg), GnRH (100 μg), vasoactive intestinal peptide (100 μg) and peptide histidine methionine (100 μg), which are known paradoxically to stimulate GH secretion in acromegaly. A paradoxical GH response (>50% above the basal) to TRH, GnRH, vasoactive intestinal peptide and peptide histidine methionine was observed in 12 (80%), 4 (27%), 5 (33%) and 2 (13%) patients, respectively. All the patients were responsive to at least one of these 4 peptides. However, none of the patients showed a positive GH response to hCRH. These results do not support a GH-releasing activity of CRH in acromegaly. Even if CRH has such an effect, it does not appear as potent as TRH, GnRH, vasoactive intestinal peptide and peptide histidine methionine. However, the possibility cannot be excluded that our negative data might have been due to the use of hCRH vs ovine CRH in earlier studies.


1976 ◽  
Vol 81 (1) ◽  
pp. 1-8 ◽  
Author(s):  
K. Maeda ◽  
Y. Kato ◽  
N. Yamaguchi ◽  
K. Chihara ◽  
S. Ohgo ◽  
...  

ABSTRACT The effect of thyrotrophin-releasing hormone (TRH) or luteinizing hormone-releasing hormone (LH-RH) on plasma levels of growth hormone (GH), prolactin (PRL), thyrotrophin (TSH), and luteinizing hormone (LH), were studied in patients with anorexia nervosa. The basal plasma GH levels were elevated in 6 of 11 patients studied. Intravenous injection of synthetic TRH (500 μg) significantly raised the plasma GH levels in 9 of 11 patients. The peak values of plasma GH after TRH ranged from 6.0 to 31.5 ng/ml. Plasma GH concentrations also increased following the administration of synthetic LH-RH (100μg) in 1 of 7 patients. The intravenous injection of saline solution caused no significant change in plasma GH in these patients. The plasma LH responses to LH-RH were significantly blunted in all patients, whereas the plasma PRL and TSH responses to TRH were almost normal in the patients examined. These results suggest that the hypothalamo-pituitary function regulating GH and LH secretion is altered in patients with anorexia nervosa.


1985 ◽  
Vol 109 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Kjell Öberg ◽  
Ingrid Norheim ◽  
Leif Wide

Abstract. The regulation of serum growth hormone was studied in 33 consecutive patients with carcinoid tumours; both diurnal serum GH and GH responses to an i.v. glucose load and TRH were assessed. Seventeen of the patients (52%) showed disturbed regulation of serum GH and 10 had at least two abnormal tests. Four patients had clinically overt acromegaly. The diurnal mean serum GH levels were higher (P < 0.001) in patients with carcinoid tumours than in control subjects and more than one third (41%) had levels in a range similar to that of acromegalic patients without carcinoid tumours. The disturbance in serum GH regulation might have been caused in some patient by tumour secreted growth hormone releasing factor(s) which act directly on pituitary somatotrophs, but other tumour-related non-specific stimulation must be considered. Carcinoid tumours should be considered in the aetiology of acromegaly.


1990 ◽  
Vol 122 (6) ◽  
pp. 745-752 ◽  
Author(s):  
Patrick Pagesy ◽  
Jacques Y. Li ◽  
Françoise Rentier-Delrue ◽  
Olivier Delalande ◽  
Yves Le Bouc ◽  
...  

Abstract. Some patients with active acromegaly have elevated plasma IGF-I concentrations with only minimal elevation of plasma GH. We compared adenomatous GH and SRIH expression in 3 such patients (patients No. 1, 2 and 3; basal plasma GH level < 4 μg/l) and in 3 acromegalic patients with high basal plasma GH level (patients No. 4, 5 and 6; 51.7 ± 16.1 μg/l, mean ± sem). By immunocytochemistry, all the tumours proved to be somatotropic adenomas. At the ultrastructural level, signs of low secretory activity were observed in adenomas from patients No. 2 and 3. Perifused adenoma cells of patients No. 1, 2 and 3 released very little GH compared with those of patients No. 4, 5 and 6 (1± 0.37 vs 51.5± 34.1 μg · (10−6 cells) · min−1, p< 0.001). Adenoma SRIH content was 65.7 and 30.6 pg/mg proteins in patients No. 1 and 2, whereas it was undetectable in the others (patients No. 4, 5 and 6). Northern blot analysis showed that the GH gene was poorly expressed in the adenomas from patients No. 1, 2 and 3 compared with the adenomas from patients No. 4, 5 and 6. SRIH mRNA was detected in all 6 adenomas. However, the signal was more intense in the adenomas from patients No. 1, 2 and 3 than in those from patients No. 4, 5 and 6. In conclusion, because of the variability of the biosynthetic and secretory potential of the somatotropic adenomas, patients harbouring this type of pituitary tumours can exhibit a wide range of plasma GH levels. In acromegaly with minimal elevation of plasma GH, the synthesis of SRIH by the adenoma cells themselves could play a role in the inhibition of GH expression.


1993 ◽  
Vol 128 (3) ◽  
pp. 197-201 ◽  
Author(s):  
Maria N Moreira-Andrés ◽  
Francisco J Cañizo ◽  
Federico Hawkins

The evaluation of growth hormone (GH) secretion is an important problem in pediatric endocrine practice. The diagnosis of GH insufficiency is based on the finding of a "blunted" GH response to GH provocative tests or on the demonstration of a decreased endogenous secretion. From a practical point of view, these methods are uncomfortable, expensive and time consuming. Recently, very sensitive specific assays to measure human GH in urine have been developed. We present a discussion of available data on these tests in order to estimate their role in the evaluation of a short or slowly growing child. The present available assays allow measuring very low levels of GH in a small sample of untreated urine. The main limitations of urinary GH measurement are the intrasubject variability, wide normal range, overlapping results in several GH secretory states and lack of information on GH pulsatility. However, most of these limitations also apply to other tests of GH secretion. The advantage of urinary GH tests is that they provide, in an easy procedure, information on serum GH concentration. There is good correlation between urinary and serum GH concentration and several findings suggest that urinary GH excretion reflects changes in plasma GH levels during the period of urine collection. Therefore, the usefulness of urinary GH measurement is that of a simpler and cheaper screening method for assessing integrated serum GH concentration in clinical practice.


1999 ◽  
Vol 14 (11) ◽  
pp. 2704-2708 ◽  
Author(s):  
Th. Kaltsas ◽  
N. Pontikides ◽  
G.E. Krassas ◽  
K. Seferiadis ◽  
D. Lolis ◽  
...  

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