Endocrine Abstracts

Introduction: Acromegaly impairs the hypothalamic-pituitary-gonadal (HPG) axis and reproductive function that causes amenorrhea and infertility. The mechanism of these disturbances is not clear. Kisspeptin and neurokinin B are very important neuropeptides regulating cyclic LH release from pituitary due to stimulation of GnRH.

Aim: The purpose of this study was to assess the role of key reproductive neuropeptides in regulation of menstrual function in patients with acromegaly.

Materials and methods: The study included 30 patients of reproductive age with acromegaly, the average age was 37 [30;42] years, BMI – 26.1 [24.7;30.5], the period from first symptoms to operation was about 5 [3;8] years. The control group consisted of 17 healthy women with regular menstrual cycle of similar age and BMI. Blood samples for neurokinin B and kisspeptin were collected into tubes containing EDTA and aprotinine, immediately centrifuged and stored at −80°C until measurement. Neuropeptides were detected by EIA (with previous extraction procedure for kisspeptin).

Results: Macroadenoma was confirmed in 26 patients, 4 patients had microadenomas. Only 16 women presented with normal menstrual cycle, 8 – amenorrhea, 2 – oligomenorrhea, 2 - menorrhagia. The levels of gonadotropins and inhibin B were statistically lower in the group of acromegaly compared to control, FSH 3.9 [2.4; 5.0] and 6.5 [5.2; 7.9], P<0.001; LH 2.9 [1.3; 4.1] and 4.6 [4.1; 5.9], P=0.002; inhibin B 32.9 [19.7; 76.7] and 79.1 [65.6; 98.6], P=0.004. Kisspeptin was also reduced in patients 7.2 [0,1;11,7] ng/ml and 12.5 [11.8;13.6], P<0.001, but there were no differences in neurokinin B level. The same trend in hormonal characteristics was revealed during analysis by groups depending on menstrual function. The presence of negative correlations was noted between kisspeptin and IGF-1, (r=0.66, P=<0.001) kisspeptin and GH (r=0.54, P=0.02) and positive correlation between kisspeptin and LH (r=0.35, P=0.006). Hyperprolactinemia was registered in 50% of patients but without correlation between prolactin and neuropeptides studied.

Conclusion: Kisspeptin plays a significant role in regulation of menstrual function in patients with acromegaly. The decrease of kisspeptin secretion is dependent on the severity of the disease and is not related to prolactin level.