Helen Lyall

Hypothalamic GLUT 4 expression: a glucose- and insulin-sensing mechanism?

The insulin-regulatable glucose transporter, GLUT 4, is expressed primarily in peripheral tissues (skeletal muscle and adipose tissue). In response to insulin this transporter moves rapidly from an intracellular storage site to the plasma membrane, thus accounting for the substantial increase in glucose uptake by these tissues following insulin stimulation. The recent finding that GLUT 4 is also expressed in the hypothalamus suggests that this brain region, which is outside the blood-brain barrier and therefore sensitive to circulating insulin, may experience stimulation of glucose uptake in response to insulin. We propose that this may allow regions of the hypothalamus to respond directly to elevated blood glucose, constituting a form of metabolic regulation by allowing circulating glucose (and therefore insulin) in concert with other mechanisms to maintain blood glucose homeostasis. We consider the possible physiological role of such a mechanism and speculate that disturbances of this mechanism may occur in endocrine disease associated with insulin resistance.

The long term health consequences of polycystic ovary syndrome.

Women with polycystic ovary syndrome have both insulin resistance and beta cell dysfunction. Consequently, they are at increased risk of developing diabetes and cardiovascular disease. Women with polycystic ovary syndrome present to clinicians at a young age and as such offer a unique opportunity to identify insulin resistant patients at an early stage. This enables the modification of risk factors and diagnosis of diabetes before the onset of macro- and micro-vascular symptoms. Increased emphasis should thus be placed on long term risk management and diabetic screening with advice on smoking, exercise and, if appropriate, weight loss. Where possible drugs that exacerbate insulin resistance should be avoided and consideration should be given to the use of insulin sensitising agents, particularly in the obese.

Turner syndrome–issues to consider for transition to adulthood

BACKGROUND Turner syndrome (TS) is associated with a spectrum of health problems across the age span, which requires particular attention during the transition period in these adolescents. AREAS OF AGREEMENT The majority of girls with TS require oestrogen replacement from puberty onwards, which is important for adequate feminization, uterine development and maintenance of bone health. There is a lifetime increased risk from autoimmune conditions like hypothyroidism, coeliac disease, hearing loss and aortic dilatation with the potential to lead to aortic dissection. A systematic and holistic approach to provision of health care in TS is needed. AREAS OF CONTROVERSY Several unanswered questions remain, including the choice of hormone replacement therapy in the young person with TS and in adulthood; the optimal mode of cardiovascular assessment; the best management and assessment prior to and during pregnancy. AREAS TIMELY FOR DEVELOPING RESEARCH The optimal model of care and transition to adult services in TS requires attention. Further research is needed in relation to cardiovascular risk assessment, pregnancy management and hormone replacement therapy in TS.

GnRH analogue in everyday gynecology, Is it possible to rationalize its use?

BACKGROUND The study was an audit of patients who attended the Menstrual Disorders Clinic at Glasgow Royal Infirmary over a five year period, and received gonadotrophin-releasing hormone analog (GnRHa). We aimed to identify the clinical indications for the use of GnRHa, and the effect of the latter in terms of symptom resolution and ultimate outcome. We aim to use this information to formulate a strategy for the use of GnRHa by targeting this expensive therapy to those situations where maximum benefit will be achieved. METHODS A retrospective case review analysis of 201 patients. RESULTS Thirty-eight percent of women presented with pelvic pain, 33% with disordered menstruation and 26% with premenstrual symptomatology. Overall, 74% of patients reported a beneficial effect of GnRHa. In the non-cyclical pelvic pain group, those patients with adhesions constituted a much greater proportion of those who did not derive benefit from GnRHa than those who did (43% vs. 16%; p<0.05; data not shown). In those patients with disordered menses, there was no difference between the diagnosis in those who did or did not derive benefit from GnRHa. Also with the exception of endometrial preparation prior to ablation and in the correction of anemia, the ultimate outcome was no different in the two groups. Of the patients with premenstrual symptomatology, the greatest proportion of those deriving benefit from GnRHa (41%) ultimately had an operative resolution. CONCLUSIONS Our results enable us to use GnRHa as a first line in those clinical situations where maximum benefit will be achieved, either in terms of symptom resolution or as a tool to identify the most appropriate therapeutic option. We can therefore rationalize our prescribing both to the benefit of the patient and to our budget.

Pre-conception maternal erythrocyte saturated to unsaturated fatty acid ratio predicts pregnancy after natural cycle frozen embryo transfer

The environment for embryo implantation and fetal growth and development is affected by maternal nutritional, metabolic and health status. The aim of this prospective, cohort study was to test whether plasma metabolic and inflammatory biomarkers can predict pregnancy resulting from in vitro fertilisation (IVF). Women with a natural menstrual cycle undergoing frozen embryo transfer (FET) were recruited and fasting baseline blood samples were collected a mean of 3.4 days prior to the luteinising hormone (LH) surge and a non-fasting blood sample was taken on the day of FET. Ongoing pregnancy was defined by positive fetal heartbeat on ultrasound scan at day 45 post LH surge. Thirty-six pregnancies resulted from FET in 143 women. In an overall stepwise multivariable analysis, erythrocyte saturated to unsaturated fatty acid ratio was positively associated with ongoing pregnancy. A similar model incorporating day of FET covariates found that erythrocyte saturated to unsaturated fatty acid ratio, erythrocyte fatty acid average chain length and plasma log-triglycerides predicted ongoing pregnancy. In conclusion, a higher peri-conceptional saturated to unsaturated fatty acid ratio predicted ongoing pregnancy after natural cycle frozen embryo transfer and may reflect a maternal nutritional status that facilitates pregnancy success in this assisted conception scenario.

Insulin action on the ovary

Polycystic ovary syndrome (PCOS) is usually defined clinically by hyperandrogenism and anovulation. Hyperinsulinaemia and insulin resistance are prominent features both in obese and nonobese women with PCOS, the latter having been shown to be more insulin resistant and hyperinsulinaemic than age- and weight-matched normal women. There is now a substantial body of evidence implicating hyperinsulinaemia in the pathogenesis of this disorder.