23 UTMJ • Volume 96, Number 3, June 2019 Primary Research Corresponding Author: Esen Yeşil - esezer@baskent.edu.tr Bağlıca Kampüsü Eskişehir Yolu 18.km 06790 Etimesgut, Ankara, Turkey Effect of weight loss diets on biochemical parameters and anthropometric measurements in prolactinoma patients Abstract Background: The aims of this study were to determine the efect of weight loss on biochemical parameters and anthropometric measurements in prolactinoma patients and to evaluate the efectiveness of weight loss diet along with medical treatment. Methods: Twenty-two patients with prolactinoma were divided into two groups and one of the groups was applied weight loss diet (diet group) while the other group was diet free (control group). Each participant was interviewed using a structured questionnaire. The biochemical parameters (fasting plasma glucose, fasting plasma insulin, prolactin, leptin, TSH, T4, cortisol, HbA1c, AST, ALT and blood lipids) of participants were analyzed and anthropometric measurements were taken. Results: There was a signifcant change in mean BMI after treatment in diet group (p=0.000). The mean level of serum prolactin decreased from 45.1±31.63 ng/dL at baseline to 12.6±8.19 ng/dL after three months in diet group (p=0.006). Despite there being no statistically signifcant diference between diet and control group in terms of baseline level of prolactin measurement (p=0.800), statistically signifcant diference between the two groups in terms of fnal level of prolactin measurement (p=0.027) was observed. There was a signifcant change in mean level of leptin after treatment in diet group (p=0.001). Conclusions: In addition to medical treatment, weight loss diets sped up the healing process for hyperprolactinemia and the reduction in body weight had positive efects on the metabolic profles of prolactinoma patients. Esen Yeşil 1 ; Gül Kızıltan 1 ; Cüneyd Anıl 2 ; Mehtap Akçil Ok 1 ; Nilüfer Bayraktar 3 1 Department of Nutrition and Dietetics, Baskent University, Ankara, Turkey 2 Ankara Güven Hospital, Ankara, Turkey 3 Department of Medical Biochemistry, Baskent University School of Medicine, Ankara, Turkey INTRODUCTION P rolactinomas are the most common type of pituitary adenomas. Macroprolactinoma is the term used for these tumors when their size is ≥1 cm. If the tumor’s size is <1cm, it’s referred to as a microprolactinoma. 1,2 Prolactinomas in adults occur more frequently in women (>70%), with the majority in the form of microprolactinoma. 2 Tumor size is generally related with prolactin (PRL) level. 2 As is well-known, increasing estrogen secretion stimulates the growth and proliferation of the lactotrophs during pregnancy. As a result, PRL secretion increases. 3 PRL is identifed as a major stimulating factor for lactation in the postpartum period. Some metabolic efects of PRL comprise of providing pancreatic cell development in the perinatal and postnatal periods to manage insulin release, nutrient uptake and body weight, to stimulating citrate production in prostatic cells, preventing the negative efects of glucocorticoids on the immune system during stress periods, reducing reproductive functions, and suppressing sexual impulsivity. In addition, PRL hormone induces adipogenesis, which inhibits lipolysis by altering the release of signifcant adipokines such as leptin, adiponectin, and interleukin (IL)-6. 4 Treatment of hyperprolactinemia reduces cardiovascular disease risk factors, endothelial dysfunction, and insulin resistance. 3,4,5 Several studies describe a higher body weight in patients with hyperprolactinemia, the exact mechanism of which is not clear. 6,7,8 A combination of factors like decreased dopaminergic tone, low adiponectin, and hypogonadism with or without associated leptin resistance could contribute to weight gain. Also, hyperprolactinemia has been linked to alteration in glucose homeostasis, insulin sensitivity, and lipid parameters. 9 PRL is known to stimulate leptin synthesis and secretion. 10 Leptin, the obese gene product, is synthesized by adipose tissue in the body. Body fat mass and body mass index (BMI) determine serum leptin level. The role of leptin is to regulate nutrient intake on the brain, modulate energy metabolism via negative feedback, and prevent the development of obesity. 11 The aims of the present study were to determine the efect of weight loss on biochemical parameters and anthropometric measurements in prolactinoma patients and to evaluate the efectiveness of a weight loss diet along with medical treatment. We analyzed the efects of the weight loss diet on the body compositions of prolactinoma patients.