IGF-I and Free Fatty Acids Isn Glucose Metabolism in Acromegaly

The Role of Insulin-like Growth Factor-I (IGF-I) and Free Fatty Acids in Insulin Resistance, Insulin Secretion and Glucose Metabolism Abnormalities in Acromegaly

Status

Completed

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT02084095

Enrollment

Registered

2014-03-11

Start date

2014-03-31

Completion date

2019-03-01

Last updated

2019-08-21

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Acromegaly

Brief summary

Background Glucose metabolism abnormalities are frequent in acromegaly. Insulin resistance (IR) correlates with the intensity of acromegaly and Insulin-like Growth factor-I (IGF-I) correlates better with IR than growth hormone (GH). Insulin secretion (IS) is significantly reduced in hyperglycemic acromegalics as compared with those with normal glucose levels. IS is independent of acromegaly intensity. The aim of this study is to show that in active acromegaly: 1) IGF-I does not cause IR but is just a better marker of acromegaly intensity than GH; 2) high GH levels induce IR through free fatty acids (FFA); 3) hyperglycemia is caused by a defficient IS on a background of IR. Methods Intensity of acromegaly will be assessed using serum levels of GH, IGF-I and IGF binding globulin-3. IR and IS will be assessd using an intravenous glucose tolerance test acording to Bergman model. FFA will be directly measured in plasma.

Interventions

None listed

Study design

Observational model

CASE_ONLY

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

18 Years to 65 Years

Healthy volunteers

Inclusion criteria

* active acromegaly based on following criteria: minimum GH in oral glucose tolerance test (OGTT) over 1 ng/mL and serum IGF-I over upper limit of normal for age and sex * age between 18 and 65 years old

Exclusion criteria

* more than one previous pituitary surgical intervention for acromegaly * present medical treatment for acromegaly (somatostatin analogs, GH-receptor blockers, dopaminergic agonists) * previous pituitary radiotherapy * present medical treatment for hyperglycemia (oral antidiabetic drugs, insulin, etc) * pituitary failure, treated or not * medical or surgical conditions which, in the oppinion of the principal investigator, could impact on study results or patient's safety * fasting blood glucose over 200 mg/dL or HbA1c over 8%. * body mass index less than 20 or over 35 kg/mp

Design outcomes

Primary

Measure	Time frame
Free fatty acids correlates significantly with insulin resistance assessed using Bergman model	2 years
The correlation coefficient between IGFBP-3 and insulin resistance assessed using Bergman model is non-inferior to the correlation coefficient between IGF-I and insulin resistance	2 years
Disposition index calculated using Bergman model is significantly reduced in subjects with glucose intolerance than in subjects with normal glucose tolerance	2 years

Secondary

Measure	Time frame
GH, IGF-I and IGFBP-3 does not correlate with disposition index	2 years
GH, IGF-I and IGFBP-3 significantly correlates with insulin resistance calculated using Bergman model	2 years
Disposition index after reduction of acromegaly activity by various treatments	3 months after surgery or start of medical treatment
GH, IGF-I and IGFBP-3 significantly correlates with free fatty acids	2 years
GH, IGF-I and IGFBP-3 does not correlate with insulin sensitivity calculated using Bergman model	2 years

Countries

Romania

Outcome results