Tyrosine metabolism in users of oral contraceptives

Serum Metabolome Changes in Relation to Prothrombotic State Induced by Combined Oral Contraceptives with Drospirenone and Ethinylestradiol

The association between hypercoagulability and use of drospirenone (DRSP) and ethinylestradiol (EE) containing combined oral contraceptives (COCs) is an important clinical concern. We have previously reported that the two formulations of DRSP combined with EE (namely, DRSP/20EE and DRSP/30EE) bring about a prothrombotic state in hemostatic traits of female users. We report here the serum metabolomic changes in the same study cohort in relation to the attendant prothrombotic state induced by COC use, thus offering new insights on the underlying biochemical mechanisms contributing to the altered coagulatory profile with COC use. A total of 78 healthy women participated in this study and were grouped as follows: control group not using oral contraceptives (n = 25), DRSP/20EE group (n = 27), and DRSP/30EE group (n = 26). Untargeted metabolomics revealed changes in amino acid concentrations, particularly a decrease in glycine and an increase in both cysteine and lanthionine in the serum, accompanied by variations in oxidative stress markers in the COC users compared with the controls. Of importance, this study is the first to link specific amino acid variations, serum metabolites, and the oxidative metabolic profile with DRSP/EE use. These molecular changes could be linked to specific biophysical coagulatory alterations observed in the same individuals. These new findings lend evidence on the metabolomic substrates of the prothrombotic state associated with COC use in women and informs future personalized/precision medicine research. Moreover, we underscore the importance of an interdisciplinary approach to evaluate venous thrombotic risk associated with COC use.

Effects of hormonal contraception on systemic metabolism: cross-sectional and longitudinal evidence

Background: Hormonal contraception is commonly used worldwide, but its systemic effects across lipoprotein subclasses, fatty acids, circulating metabolites and cytokines remain poorly understood.

Methods: A comprehensive molecular profile (75 metabolic measures and 37 cytokines) was measured for up to 5841 women (age range 24–49 years) from three population-based cohorts. Women using combined oral contraceptive pills (COCPs) or progestin-only contraceptives (POCs) were compared with those who did not use hormonal contraception. Metabolomics profiles were reassessed for 869 women after 6 years to uncover the metabolic effects of starting, stopping and persistently using hormonal contraception.

Results: The comprehensive molecular profiling allowed multiple new findings on the metabolic associations with the use of COCPs. They were positively associated with lipoprotein subclasses, including all high-density lipoprotein (HDL) subclasses. The associations with fatty acids and amino acids were strong and variable in direction. COCP use was negatively associated with albumin and positively associated with creatinine and inflammatory markers, including glycoprotein acetyls and several growth factors and interleukins. Our findings also confirmed previous results e.g. for increased circulating triglycerides and HDL cholesterol. Starting COCPs caused similar metabolic changes to those observed cross-sectionally: the changes were maintained in consistent users and normalized in those who stopped using. In contrast, POCs were only weakly associated with metabolic and inflammatory markers. Results were consistent across all cohorts and for different COCP preparations and different types of POC delivery.

Conclusions: Use of COCPs causes widespread metabolic and inflammatory effects. However, persistent use does not appear to accumulate the effects over time and the metabolic perturbations are reversed upon discontinuation. POCs have little effect on systemic metabolism and inflammation.

Phase of menstrual cycle affects lysine requirement in healthy women

The aim of this study was to investigate whether the phases of the menstrual cycle affect lysine requirement in healthy adult females, as determined by the indicator amino acid oxidation (IAAO) method. Five healthy females with regular menstrual cycles were studied at seven graded levels of lysine intake, in random order, with an oral [13C]phenylalanine tracer protocol in both the follicular and luteal phases. A total of 14 studies were conducted for each subject. Breath and plasma samples were collected according to the standard IAAO protocol. Serum 17beta-estradiol and progesterone concentrations were measured on each IAAO study day. The rate of release of 13CO2 from [13C]phenylalanine oxidation (F13CO2) was measured, and a two-phase linear regression crossover model was applied to determine lysine requirement. F13CO2 was higher during the luteal phase (P < 0.001) and was positively associated with serum concentrations of 17beta-estradiol and progesterone. The F13CO2 data were adjusted for subjects and sex hormones and used to define breakpoints for lysine requirements. The lysine requirement of healthy females in the luteal phase was 37.7 mg.kg(-1).day(-1) and higher (P = 0.025) than that of females in the follicular phase (35.0 mg.kg(-1).day(-1)). At all lysine intake levels, plasma amino acids were lower and phenylalanine oxidation was higher in the luteal relative to the follicular phase. Therefore, we reason that the higher lysine requirement observed in the luteal phase is probably due to higher amino acid catabolism.

Testing the tyrosine/catecholamine hypothesis of oral contraceptive-induced psychological side-effects: a controlled study on triphasil

BACKGROUND

This study was conducted to probe the existence of oral contraceptive (OC)-induced psychological side effects that might be undetectable by psychometric testing.

METHODS

Triphasil was administered during six complete menstrual cycles to young never-OC-users. Plasma Tyr and Trp/Sigma-respective competitor neutral amino acids (NAA) ratio and concentrations of other amino acids (AA), known to be involved in the functioning of the central nervous system (CNS) and the synthesis of neurotransmitters, in particular, were used as biochemical markers to assess this likelihood. Factors known to influence plasma AA concentrations such as cortisol and pyridoxal phosphate (PLP, active form of vitamin B6), both modulators of AA intestinal absorption, were examined.

RESULTS

Dietary supply of amino acid substrates (precursors) and blood levels of coenzyme/cofactor (vitamin B6 and iron) involved were adequate in both groups and were kept constant throughout the treatment. The rise in plasma cortisol, known to be stimulated under the action of estrogen, was significant (p < 0.05) after the first menstrual cycle and remained higher (although not significantly) than mean baseline and reference normal values at the end of the 6-month OC treatment. Plasma Trp/Sigma-specific competitor NAA ratio remained unchanged whereas Tyr/Sigma-specific competitor NAA ratio was significantly (p < 0.02) reduced after the sixth artificial menstrual cycle.

CONCLUSION

Although plasma AA biochemical markers cannot accurately assess CNS activity, they seem to be more sensitive than a comprehensive psychometric testing (MMPI) in assessing OC-induced psychological changes.