Increased visceral adiposity and cortisol to cortisone ratio in adults with congenital lifetime isolated GH deficiency.

CONTEXT: Adult-onset GH deficiency (GHD) increases visceral adiposity and the activity of the enzyme 11ß-hydroxysteroid dehydrogenase, which converts cortisone (E) to cortisol (F), both linked to insulin resistance and increased cardiovascular risk. Conversely, we reported that adults with congenital isolated GHD (IGHD) have increased insulin sensitivity. OBJECTIVE: To assess the type of fat distribution and the amount of visceral and sc fat and to correlate them to the F/E ratio in adults with untreated IGHD due to a mutation in the GHRH receptor gene. METHODS: Body composition was assessed by dual-energy x-ray absorptiometry, thickness of sc and visceral fat was measured by sonography, and serum F and E were measured in 23 IGHD subjects and 21 age-matched controls. RESULTS: Waist/hip ratio (WHR), trunk fat, and trunk/extremity fat (TR/EXT) ratio were higher in IGHD subjects. Visceral fat index (VFI) (but not sc fat index [SFI]) was higher in IGHD. F and F/E ratio were also higher in IGHD. In all 44 individuals, WHR correlated with TR/EXT ratio, thickness of visceral fat, VFI/SFI ratio, F, and F/E ratio. TR/EXT ratio correlated with visceral fat thickness, VFI/SFI ratio, and F. Age had a significant effect on VFI and on F/E ratio. Body mass index SD score and WHR have a similar significant effect on TR/EXT ratio and on F/E ratio. CONCLUSIONS: Lifetime congenital untreated IGHD causes increased visceral adiposity with a high F/E ratio. However, the increased insulin sensitivity suggests that visceral adiposity needs a minimal GH secretion to translate into increased insulin resistance.

Isolated GH deficiency due to a GHRH receptor mutation causes hip joint problems and genu valgum, and reduces size but not density of trabecular and mixed bone.

CONTEXT: The GH/IGF-I axis is important for bone growth, but its effects on joint function are not completely understood. Adult-onset GH-deficient individuals have often reduced bone mineral density (BMD). However, there are limited data on BMD in adult patients with untreated congenital isolated GH-deficient (IGHD). We have shown that adult IGHD individuals from the Itabaianinha, homozygous for the c.57+1G>A GHRHR mutation, have reduced bone stiffness, but BMD and joint status in this cohort are unknown. OBJECTIVE: The goal is to study BMD, joint function, and osteoarthritis score in previously untreated IGHD adults harboring the c.57+1G>A GHRHR mutation. DESIGN: This is a cross-sectional study. METHODS: Areal BMD by dual-energy X-ray absorptiometry was measured in 25 IGHD and 23 controls (CO). Volumetric BMD (vBMD) was calculated at the lumbar spine and total hip. Joint function was assessed by goniometry of elbow, hips, and knees. X-rays were used to measure the anatomic axis of knee and the severity of osteoarthritis, using a classification for osteophytes (OP) and joint space narrowing (JSN). RESULTS: Genu valgum was more prevalent in IGHD than CO. The osteoarthritis knees OP score was similar in both groups, and knees JSN score showed a trend to be higher in IGHD. The hips OP score and JSN score were higher in IGHD. Areal BMD was lower in IGHD than CO, but vBMD was similar in the two groups. Range of motion was similar in elbow, knee, and hip in IGHD and CO. CONCLUSIONS: Untreated congenital IGHD due to a GHRHR mutation causes hip joint problems and genu valgum, without apparent clinical significance, reduces bone size, but does not reduce vBMD of the lumbar spine and hip.

Lifetime congenital isolated GH deficiency does not protect from the development of diabetes.

OBJECTIVES: Adult subjects with untreated, lifetime, isolated GH deficiency (IGHD) due to a homozygous GHRH receptor gene mutation (MUT/MUT) residing in Itabaianinha, Brazil, present with lower BMI, higher prevalence of impaired glucose tolerance (IGT), increased insulin sensitivity (IS), and reduced ß-cell function (ßCF) when compared with non-BMI-matched homozygous normal controls. However, the prevalence of diabetes mellitus (DM) in this cohort is unknown. Comparing their IS and ßCF with BMI-matched individuals heterozygous for the same mutation (MUT/N) may be useful to elucidate the role of the GH-IGF1 axis in IS and ßCF. The purposes of this work were to verify the prevalence of IGT and DM in adult MUT/MUT subjects from this kindred and to compare IS and ßCF in MUT/MUT and MUT/N. DESIGN: Cross-sectional study. METHODS: We studied most (51) of the living IGHD adults of this kindred who are GH naive. The oral glucose tolerance test (OGTT) could be performed in 34 subjects, fasting glucose was measured in 15, while two had a previous diagnosis of DM. The OGTT results of 24 MUT/MUT subjects were compared with those of 25 BMI-matched MUT/N subjects. IS was assessed by homeostatic model assessment of insulin resistance (HOMA-IR), quantitative IS check index, and oral glucose IS index for 2 and 3 h. ßCF was assayed by HOMA-ß, insulinogenic index, and the area under the curve of insulin:glucose ratio. RESULTS: The prevalence of DM and IGT in IGHD was 15.68 and 38.23% respectively. IS was increased and ßCF was reduced in MUT/MUT in comparison with MUT/N. CONCLUSIONS: Lifetime, untreated IGHD increases IS, impairs ßCF, and does not provide protection from diabetes.