scholarly journals Clinical Evaluation of Growth Hormone Secretion in Cattle Using Insulin Tolerance Test

2003 ◽  
Vol 65 (7) ◽  
pp. 809-812
Author(s):  
Masafumi OGURO ◽  
Hirotaka ISHIKAWA ◽  
Hiromichi OHTSUKA ◽  
Fumio HOSHI ◽  
Seiichi KAWAMURA
Keyword(s):  
Growth Hormone ◽  
Clinical Evaluation ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Tolerance Test ◽  
Insulin Tolerance Test ◽  
Insulin Tolerance

Test of growth hormone secretion in adults: poor reproducibility of the insulin tolerance test

1995 ◽  
Vol 133 (3) ◽  
pp. 305-312 ◽  
Author(s):  
Hans C Hoeck ◽  
Peter Vestergaard ◽  
Poul E Jakobsen ◽  
Peter Laurberg
Keyword(s):  
Growth Hormone ◽  
Gh Deficiency ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Tolerance Test ◽  
Insulin Tolerance Test ◽  
Repeated Testing ◽  
Provocative Test ◽  
Insulin Tolerance ◽  
Gh Deficiency In Adults

Hoeck HC, Vestergaard P, Jakobsen PE, Laurberg P, Test of growth hormone secretion in adults: poor reproducibility of the insulin tolerance test. Eur J Endocrinol 1995;133:305–12. ISSN 0804–4643 The insulin tolerance test (ITT) is regarded as the most reliable provocative test in the diagnosis of growth hormone (GH) deficiency in adults. In the present study the test was evaluated by investigating the range of GH responses in normal adult males and females and the intra-individual reproducibility of the test. Sixteen healthy non-obese adults, eight males (median age 31.5 years) and eight females (median age 31.8 years) were tested twice with the ITT, with a minimum of 72 h between each test. The females were tested between day 3 and day 10 of their menstrual cycles. Adequate hypoglycemia was achieved in all cases with a median nadir blood glucose of 1.3 mmol/l (range 0.8–2.0). Growth hormone in serum was measured by immunoradiometric assay and low values were confirmed by a different assay. Median peak GH concentration responses to the ITT were: in males 27.9 μg/l, range 5.0–71.1 (test 1) and 30.5 μg/l, range 7.9–69.5 (test 2); and in females 9.0 μg/l, range 4.1–17.9 (test 1) and 8.4 μg/l, range 0.09–42.4 (test 2). The rise in GH concentration during the ITT was higher in males than in females. In the males, all stimulated GH values were ≥5.0 μg/l. In the females, four out of 16 tests gave values below 5.0 μg/l and in one test the GH value was around the detection limit of the assays. There was poor reproducibility during repeated testing, with no correlation between the results of the two tests. The results did not correlate to the magnitude of the hypoglycemia. The results of this study illustrate the complexity of the regulation of GH secretion and indicate that the ITT is less useful for diagnosing GH deficiency in adults than previously anticipated. The diagnosis of GH deficiency in adults and especially in adult females should not be based on the results of a single ITT alone. Hans C Hoeck, Department of Endocrinology, Aalborg Regional Hospital, Reberbansgade, DK-9000 Aalborg, Denmark

Evaluation of growth hormone response to insulin-induced hypoglycaemia in dairy cattle during a 670-day lactation

2014 ◽  
Vol 54 (9) ◽  
pp. 1323 ◽  
Author(s):  
L. C. Marett ◽  
M. J. Auldist ◽  
W. J. Wales ◽  
K. L. Macmillan ◽  
K. DiGiacomo ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Tolerance Test ◽  
Insulin Tolerance Test ◽  
Growth Hormone Response ◽  
Delayed Response ◽  
Hormone Response ◽  
Plasma Growth Hormone ◽  
Insulin Tolerance

Plasma growth hormone secretion in response to insulin-induced hypoglycaemia was evaluated in cows undergoing an extended lactation. Twelve multiparous Holstein-Friesian cows that calved in late winter and were managed for a 670-day lactation by delaying mating. Four experimental periods of 40 days commenced at ~73, 217, 422 and 520 (±9.1; mean ± s.d.) days in milk (DIM) during which cows were individually offered a diet of perennial ryegrass (73 and 422 DIM) or pasture hay and pasture silage (217 and 520 DIM) supplemented with either 1 kg DM grain (CONT) or 6 kg DM grain (GRAIN). Cows were fitted with jugular catheters during the final week of each experimental period. Seven blood samples over a 24-h period were collected and an insulin tolerance test was performed on each cow using a dose of 0.12 µU insulin/kg liveweight at ~100, 250, 460 and 560 DIM. This resulted in an increase in plasma growth hormone concentration occurring at 100 DIM, an intermediate and delayed response at 250 DIM, and no response at both 460 and 560 DIM. Cows in the CONT treatment had higher basal plasma growth hormone concentrations and tended to have a greater peak growth hormone response than GRAIN cows. The growth hormone response at 100 and 250 DIM is likely a homeorhetic mechanism to support milk yield during early-mid lactation. These observations are consistent with the known actions of growth hormone to promote lipid mobilisation, hepatic glucose production and an overall state of catabolism. With further research, the insulin tolerance test may be a useful tool to identify cows with greater growth hormone secretory response and increased milk production or persistency.

L-DOPA INDUCED GROWTH HORMONE SECRETION. COMPARISON WITH INSULIN TOLERANCE TEST, ARGININE INFUSION AND SLEEP INDUCED GH-SECRETION

1974 ◽  
Vol 77 (2) ◽  
pp. 241-249 ◽  
Author(s):  
C. Lucke ◽  
B. Höffken ◽  
K. D. Morgner
Keyword(s):  
Growth Hormone ◽  
Hormone Secretion ◽  
False Negative ◽  
Growth Hormone Secretion ◽  
Suppressive Effect ◽  
Tolerance Test ◽  
Insulin Tolerance Test ◽  
Arginine Infusion ◽  
Negative Results ◽  
Insulin Tolerance

ABSTRACT Plasma growth hormone (GH) levels following oral stimulation with 500 mg of L-dopa were determined and compared with those following arginine infusion, insulin tolerance test (ITT) and sleep induced secretion. Peak values following L-dopa were 13.3 ± 2.5 ng/ml and not different from those following arginine (16.4 ± 3. 3ng/ml) and those during nocturnal sleep (14.7 ± 1.2 ng/ml), but significantly less than GH peaks during ITT (24.9 ± 3.4 ng/ml). The rate of false negative results to L-dopa was 15% and seems to be higher than following other stimuli. – In contrast to the stimulatory effect in healthy subjects L-dopa had a suppressive effect on the GH levels in 4 patients with acromegaly.

Comparison of pituitary–adrenal responsiveness between insulin tolerance test and growth hormone-releasing peptide-2 test: A pilot study

Peptides ◽  
2010 ◽  
Vol 31 (4) ◽  
pp. 657-661 ◽  
Author(s):  
Toshiko Kano ◽  
Hitoshi Sugihara ◽  
Mariko Sudo ◽  
Mototsugu Nagao ◽  
Taro Harada ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Pilot Study ◽  
Tolerance Test ◽  
Insulin Tolerance Test ◽  
Insulin Tolerance

scholarly journals Diagnostic Usefulness of the Growth Hormone-Releasing Peptide-2 Test as a Substitute for the Insulin Tolerance Test in Hypopituitarism

2008 ◽  
Vol 55 (4) ◽  
pp. 777-783 ◽  
Author(s):  
Kazunori KAGEYAMA ◽  
Takeshi NIGAWARA ◽  
Satoru SAKIHARA ◽  
Shinobu TAKAYASU ◽  
Ken TERUI ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Tolerance Test ◽  
Insulin Tolerance Test ◽  
Insulin Tolerance ◽  
Diagnostic Usefulness

scholarly journals A Cross-Sectional Study to Evaluate the Safety and Efficacy of the Insulin Tolerance Test

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A621-A622
Author(s):  
Ahmad Yehia Ghamlouche ◽  
Fouad Alzaroui ◽  
Tamara Altaweel ◽  
Adel Alwakeedi ◽  
Hassan A Khan ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Adverse Effects ◽  
Adverse Events ◽  
Tolerance Test ◽  
Insulin Tolerance Test ◽  
Clinical Safety ◽  
Safety And Efficacy ◽  
Insulin Tolerance ◽  
Normal Ranges ◽  
History Of

Abstract Introduction: The insulin tolerance test (ITT) is the current standard for the diagnosis of pituitary diseases such as growth hormone deficiencies (GHD). Previous reports indicated that the ITT as having a high adverse event profile, and the cosyntropin test as being sensitive enough to diagnose GHD in adults. The purpose of this study is to validate the safety and efficacy of the ITT. Design: Over 400 ITT tests were conducted over the course of 3 years from (2017-2020) at our facility. This study is only focused on adult physiology (Cohort Age 16 - 78) and excludes any pediatric tests. An important measure, time spent in critical state (Tc), is done to know the expected time a patient is to remain hypoglycemic, both for patient expectations and clinician logistics. We did not use a CGM, instead drew blood samples on set intervals for glucose measurements. Since the measurements aren’t continuous, a consistent overestimation is done for all subject encounters to capture the maximum time spent in hypoglycemia. Insulin like growth factor one (IGF-1) was measured before the test was conducted and is listed in the spreadsheet. Growth hormone peaks were and the time to reach that peak (Tp) were also measured. This time is calculated from the listed time of the first dosage of insulin to the time of the GH peak. Other measures listed in the spreadsheet include a brief medical history of the patient, their age, weight, gender, and the blood pressure and heart rate measured at test completion. Any immediate interventions such as intravenous fluid injections were listed. Symptoms of hypoglycemia are excluded as a complication of the test. This is due to the inherent nature of the ITT whose goal is to drop one’s blood sugar past normal ranges. Results: Our results show (0.45%) rate of adverse events. 2 patients in the entire cohort suffered from seizures during their hypoglycemic period. Both of them were successfully aborted with Ativan, and patients were monitored until recovery from post ictal state and discharged home with stable vitals and no acute symptoms. It was later discovered these patients had remote history of epilepsy and should’ve been excluded from this trial. Of the remaining 448 subject encounters, (20%) of them required urgent intervention to BP. Zero of those patients suffered any other symptoms or ongoing adverse effects. 5 patients underwent the ITT twice, again, with no adverse effects. Conclusion: No permanent adverse events or hospitalizations were reported. Based on our findings the clinical safety concerns of the ITT test are minimal compared with the benefit of obtaining an accurate diagnosis in this patient cohort, if done within the correct protocol. Using IGF-1 measures as a determinant of GHD is wildly inaccurate as seen in our results. Combining IGF-1 with the Cosyntropin test is not a good enough measure for diagnosing GHD. The ITT test remains the most accurate and reliable test available today.

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