Endocrine Abstracts

The aim: To estimate secretory and proliferative activity of pituitary adenoma (isolated somatotropinoma (ST) and somatomammotropinoma (SMT).

Subjects and methods: The study included 133 patients (total group: 45 male/88 female), aged 44.0±12.5 year old with acromegaly (95 – with ST and 38 – with SMT). There were estimated patient’s age, age of manifestation of acromegaly (age_manifest.), duration of period before diagnosis (DPD) and duration of disease (DD), total secretory activity of adenoma (TSA) (ng/ml), secretory activity of pituitary adenoma unit (SAUPA) (ng/ml per cm³) and tumor growth rate (TGR) (cm³/years). The data are given as Me and nonlinear regression model equations parameters.

Results: In the total group the tumor volume (VT) was associated with age_manifest. (r=−0.41; P=0.006), plasma GH (r=0.37; P=0.04l); TSA (r=0.38; P=0.004), TGR (r=0.82; P<0.00001) and SAUPA (r=−0.36; P=0.006). In the SMT-group VT was higher, than in a ST-group (Me 5.21 cm and 2.42 cm³, respectively; P=0.002) and associated with GH level (r=0.53; P=0.03), but not with prolactin (PRL). The TSA in ST/SMT-group is associated with TGR (r=−0.36; P=0.008) and SAUPA (r=0.54; P<0.0001). It’s identified association between TGR and SAUPA (r=0.56; P<0.0001). It’s set that in a SMT-group TSA were higher, than in a ST-group (Me 28.9 and Me 12.5 ng/ml, respectively; P=0.02). The VT is associated with TSA both in ST-group (r=0.54; P=0.0006) and in SMT-group (r=0.47; P=0.04). SAUPA in ST and SMT groups did not differ, however VT is associated with SAUPA in both groups ((r=−0.54; P=0.0007) and (r=−0.75; P=0.0002), respectively). In a SMT-group the VT is associated with PRL (r=0.79; P<0.00001), which determines 63.4% his dispersion, in that time as a GH only 22.1%.

Conclusion: The presence of association between the clinical flow of acromegaly and secretory and proliferative activity of GH-secreting adenoma, in particular connection between «aggressive» clinical flow a SMT with their high secretory and proliferative activity. It is set that considerable duration of DPD and DD is inherent the of high «benign» clinical flow of acromegaly at in relation to low TSA, to «malignant» – insignificant DPD and DD at high TSA of GH-secreting pituitary adenoma. The intensity of the tumor process in patients with acromegaly is associated with the age of manifestation, which results in a decrease in the proliferative and secretory activity of a GH-secreting pituitary adenoma with age.

Keywords: acromegaly, secretory, proliferative activity, pituitary adenoma, tumor growth rate.