Gender- and age-related differences in the endocrine parameters of acromegaly

Abstract

Acromegaly is a severe slow-developing disease associated with a poor prognosis for cardiovascular disease. To evaluate the impact of age and gender on the severity of the disease, 151 de novo patients with acromegaly (79 women, 72 men, age range 19-77 yr) were included in this open retrospective multi-center cohort study. Basal GH and IGF-I levels, GH response after glucose load and maximal tumor diameter at MRI were measured in all patients at diagnosis. Fasting GH levels and maximal tumor diameter were similar in women and men, while serum IGF-I levels were lower (664.9+/-24.9 vs 755.9+/-32 microg/l; p=0.02) and GH nadir after glucose load was higher (27.5+/-3.7 vs 18.5+/-2.2 microg/l; p=0.04) in women than in men. In both sexes, patients' age was negatively correlated with basal and nadir GH, IGF-I levels and tumor size; fasting GH levels were positively correlated with IGF-I levels and nadir GH after glucose. No interaction between age and gender was found on biochemical and morphological parameters. At diagnosis, elderly patients with acromegaly have lower GH and IGF-I levels, lower GH nadir after glucose load and smaller adenomas than young patients. Women have lower IGF-I levels but higher GH nadir after glucose load than men. These age and gender differences should be considered to appropriately evaluate the activity of acromegaly throughout a life-span.

Gender differences in serum GH and IGF-I levels and the GH response to dynamic tests in patients with acromegaly

“…We observed that the IGF-I/GH ratios in female were significantly lower than those ratios in male only in patients with in the age ≤ 50 group. Our results were consistent with the data of Colao et al [18] who observed that basal IGF-I levels were significantly lower in female than in male only in their youngest group. Moreover, IGF-I/ GH ratio in excluded 14 patients with concomitant…”

“…In agreement with these previous data, the nadir GH/basal GH ratios in the present study were not significantly different between male and female with acromegaly. In contrast, Colao et al reported a significantly higher GH suppression rate after a glucose load in male patients over 40 years of age compared with age-matched female patients [18]. In the preceding study, GH levels after an OGTT were suppressed below 50% of baseline in 40% of the patients while the rate was only 4.5% (3/67) in our patients.…”

“…Whether the GH response to a glucose load is dependent on gender has been investigated [18,19,20,21]. Serum GH concentrations are lower in male than in female both at baseline and at the post glucose GH nadir in patients with acromegaly as well as in normal subjects [19,20,21].…”

Low Serum IGF-I/GH Ratio Is Associated with Abnormal Glucose Tolerance in Acromegaly

“…In the present study, there was a positive correlation between serum GH and IGF-I levels, as previously reported [14, 22], indicating that the group was appropriate. Insulin secreting ability, HOMA-β in the IGT+DM group was significantly lower than that in the NGT group, supporting the previous report that the onset of DM depended on the ability of insulin secretion in acromegaly [2].…”

Pituitary-independent effect of octreotide on IGF1 generation

“…Intrinsic and extrinsic oestrogens antagonise the effect of GH on IGF1 generation in healthy subjects (18), patients with GH deficiency (19) and acromegaly (20,21). Conversely, obesity increases GH sensitivity (22)(23)(24), a finding that may be at least partially explained by elevated insulin levels (25).…”