Plasma Oxytocin Concentration in Pre- and Postmenopausal Women: Its Relationship with Obesity, Body Composition and Metabolic Variables

Abstract

Objective: To investigate the relationship between oxytocin, menopause and obesity. Methods: A cross-sectional analysis on 56 obese (OB; 28 premenopausal) and 53 normal-weight women (NW; 27 premenopausal) was performed by measurement of oxytocin, leptin, adiponectin, gonadotropins, sex steroids, glucose, and lipid homeostasis as well as DXA assessment of fat mass (%FM) and fat-free mass (FFM). Results: Women from NW and OB groups were comparable for age but differed in anthropometric measures. In our cohorts, menopause was not associated with changes in gluco-lipid homeostasis and %FM, while FFM was lower in postmenopausal women from both study groups (p < 0.05). In each group, leptin was unaltered, and adiponectin only marginally changed across menopause, while oxytocin levels were lower in post- than in premenopausal women (NW: p < 0.05; OB: p < 0.005), and lower in OB than NW women, either when assessed as whole groups or if stratified by menopause (p < 0.001). In correlation analysis, inverse associations related oxytocin to menopause, obesity, and adiposity-related measures. BMI (p < 0.0001) and menopause independently predicted oxytocin levels (p < 0.001), but their interaction was null (p = 0.5). Conclusions: Obesity and menopause are independent negative predictors of plasma oxytocin. Longitudinal studies should clarify the role of oxytocin on weight modifications experienced around and after menopause.

The role of oxytocin in regulation of appetitive behaviour, body weight and glucose homeostasis

“…There is also evidence for higher peripheral OXT levels in individuals with excess energy stores, including overweight/obese women and men . However, in a number of studies of obese adults with a high prevalence of type 2 diabetes or insulin resistance and children with insulin resistance, OXT levels were low; this may be directly related to impaired glucose homeostasis as individuals with type 1 or type 2 diabetes have low OXT levels . Some studies in individuals with type 2 diabetes or insulin resistance and overweight/obesity have found that lower OXT levels are associated with increased features of metabolic syndrome .…”

“…However, in a number of studies of obese adults with a high prevalence of type 2 diabetes or insulin resistance and children with insulin resistance, OXT levels were low; this may be directly related to impaired glucose homeostasis as individuals with type 1 or type 2 diabetes have low OXT levels . Some studies in individuals with type 2 diabetes or insulin resistance and overweight/obesity have found that lower OXT levels are associated with increased features of metabolic syndrome . However, one study of older men (mean weight 80 kg) (a minority of whom had type 2 diabetes) found that higher OXT levels were associated with greater weight and metabolic syndrome, and another of men and women across a wide spectrum of weights with insulin resistance in those with obesity reported higher OXT levels were associated with greater body mass index and insulin resistance (homeostatic model assessment of insulin resistance [HOMA‐IR]) .…”

Associations of oxytocin with metabolic parameters in obese women of childbearing age

“…This result was in agreement with some previous reports. However, most of the related studies were done on postmenopausal women or women after ovariectomy [14,24]. Oxytocin is an anorexigenic neuropeptide that controls metabolic homeostasis mainly via regulating food intake and energy expenditure [25].…”

“…Oxytocin, a hypothalamic hormone that enters the peripheral circulation through the posterior pituitary, regulates a range of physiological processes, including reducing caloric intake, increasing energy expenditure, improving fat metabolism, and maintaining glucose homeostasis and insulin sensitivity [11][12][13]. Some studies have confirmed the association of plasma oxytocin with obesity, and oxytocin may play an important role in control of body weight in women [14]. Decreased oxytocin concentration is directly correlated with hypertension, dyslipidaemia, insulin resistance, and type 2 diabetes mellitus [15][16][17].…”

Anxiety Amplifies Plasma Oxytocin Levels in Older Individuals with type 2 Diabetes. Findings from the Cross-Sectional KORA-Age Study.

“…Although these intervention studies showed bene cial effects of OXT on T2DM-related metabolic pro les, how T2DM may affect endogenous OXT levels is still poorly understood. While previous studies in young to middle-aged adults have found an association between lower OXT levels and T2DM [6][7][8][9][10][11], others have reported con icting ndings with higher levels of OXT in metabolic disorders [12][13][14]. Furthermore, most studies investigating the association between OXT and T2DM are small-sized and stem from sex-speci c young populations.…”