Response of the pituitary-adrenal axis to hypoglycemic stress in women with the polycystic ovary syndrome

Low glucose availability stimulates progesterone production by mouse ovaries in vitro

Steroid production by the ovary is primarily stimulated by gonadotropins but can also be affected by biological cues that provide information about energy status and environmental stress. To further understand which metabolic cues the ovary can respond to, we exposed gonadotropin-stimulated mouse ovaries in vitro to glucose metabolism inhibitors and measured steroid accumulation in media. Gonadotropin-stimulated ovaries exposed to 2-deoxy-d-glucose increased progesterone production and steroidogenic acute regulatory protein mRNA levels. However, oocytes and granulosa cells in antral follicles do not independently mediate this response because targeted treatment of these cell types with a different inhibitor of glucose metabolism (bromopyruvic acid) did not affect progesterone production. Elevated progesterone production is consistent with the homeostatic role of progesterone in glucose regulation in mammals. It also may regulate follicle growth and/or atresia within the ovary. These results suggest that ovaries can regulate glucose homeostasis in addition to their primary role in reproductive activity.

Exaggerated glucagon responses to hypoglycemia in women with polycystic ovary syndrome

CONTEXT

Premenopausal women have blunted counter-regulatory hormone responses (CRR) to hypoglycemia compared to men. Postmenopausal women have CRR similar to men; the premenopausal pattern can be restored by estrogen. However, glucagon and pancreatic polypeptide (PP) responses remain lower in postmenopausal women than in men. Since hyperandrogenemia contributes to the metabolic phenotype of polycystic ovary syndrome (PCOS), we hypothesize that CRR to hypoglycemia especially of glucagon and PP is exaggerated in premenopausal women with PCOS compared to premenopausal control women.

STUDY SUBJECTS AND METHODS

Ten obese women with PCOS and 9 control women of similar ethnicity, age and BMI underwent determination of CRR in response to hypoglycemia during 180-min 60mU/m²/min insulin dose hypoglycemic clamp with isotopic assessment of endogenous glucose production (EGP). To assess CRR to hypoglycemia, glucagon, cortisol, growth hormone (GH), epinephrine, norepinephrine, PP, lactate, free fatty acid (FFA), β-hydroxybutyrate, and glycerol levels were sampled at 15-min intervals throughout the clamp.

MAIN FINDINGS

Incremental glucagon levels were ~3-fold higher during hypoglycemia (P=0.03) in PCOS. Postabsorptive, steady-state and incremental GH, cortisol, epinephrine, norepinephrine, PP, FFA, glycerol and β-hydroxybutyrate did not differ. At target glucose levels of ~52mg/dL, insulin mediated glucose disposal (IMGD) was decreased by ~40% (P=0.02) in PCOS, compared to control women, despite ~20% higher steady-state insulin levels (P=0.03). Neither postabsorptive nor steady-state EGP differed. However, postabsorptive lactate levels were ~50% higher (P=0.02). PCOS status (P=0.04) and IMGD (P=0.02) predicted the differential glucagon response to hypoglycemia in separate regression models, however, neither parameter remained an independent predictor in a combined model.

PRINCIPAL CONCLUSIONS

Glucagon responses were increased in PCOS, whereas other CRR did not differ. Women with PCOS were insulin resistant under hypoglycemic conditions and higher postabsorptive lactate levels in PCOS were consistent with this finding. Insulin resistance may have contributed to exaggerated glucagon response to hypoglycemia in PCOS.

Birth weight and polycystic ovary syndrome in adult life: is there a causal link?

Objectives

Several studies have demonstrated associations of birth weight with metabolic and reproductive abnormalities in adults. The aim of this study was to investigate the birth weight in women with PCOS and its correlation with clinical and biochemical characteristics of the syndrome.

Materials and Methods

We studied 288 women with PCOS according to the NIH criteria and 166 women with normal cycle and without clinical hyperandrogenism. Birth weight and anthropometric characteristics were recorded, and levels of serum androgens, SHBG, insulin and fasting glucose were measured.

Results

Birth weight data were available for 243/288 women with PCOS and age- and BMI-matched 101/166 controls. No differences were found (p> 0.05) in birth weight among women with PCOS and normal controls. Birth weight of PCOS women was negatively correlated with DHEAS levels (p = 0.031, r = -0.143) and positively correlated with waist circumference (p <0.001, r = 0.297) and body mass index (BMI) (p = 0.040, r = 0.132). Birth weight of controls was negatively correlated with SHBG levels (p = 0.021, r = -0.234). Women from both groups were further divided in 6 categories according to birth weight (A. <2.500 gr, B. 2.501-3.000 gr, C. 3.001-3.500 gr, D. 3.501-4.000 gr, E. 4.001-4.500 gr, F. > 4.500 gr). No statistically significant differences were observed in the distribution percentages between PCOS women and controls. (A. 7% vs 7.9%, B. 26.8% vs 20.8%, C. 39.1% vs 48.5%, D. 21.4% vs 20.8%, E. 4.9% vs 2%, F. 0.8% vs 0%), (in all comparisons, p> 0.05).

Conclusions

Women with PCOS do not differ from controls in birth weight distribution. However, birth weight may contribute to subtypes of the syndrome that are characterized by adrenal hyperandrogenism and central obesity.

DHEA, DHEAS and PCOS

Approximately 20-30% of PCOS women demonstrate excess adrenal precursor androgen (APA) production, primarily using DHEAS as a marker of APA in general and more specifically DHEA, synthesis. The role of APA excess in determining or causing PCOS is unclear, although observations in patients with inherited APA excess (e.g., patients with 21-hydroxylase deficient congenital classic or non-classic adrenal hyperplasia) demonstrate that APA excess can result in a PCOS-like phenotype. Inherited defects of the enzymes responsible for steroid biosynthesis, or defects in cortisol metabolism, account for only a very small fraction of women suffering from hyperandrogenism or APA excess. Rather, women with PCOS and APA excess appear to have a generalized exaggeration in adrenal steroidogenesis in response to ACTH stimulation, although they do not have an overt hypothalamic-pituitary-adrenal axis dysfunction. In general, extra-adrenal factors, including obesity, insulin and glucose levels, and ovarian secretions, play a limited role in the increased APA production observed in PCOS. Substantial heritabilities of APAs, particularly DHEAS, have been found in the general population and in women with PCOS; however, the handful of SNPs discovered to date account only for a small portion of the inheritance of these traits. Paradoxically, and as in men, elevated levels of DHEAS appear to be protective against cardiovascular risk in women, although the role of DHEAS in modulating this risk in women with PCOS remains unknown. In summary, the exact cause of APA excess in PCOS remains unclear, although it may reflect a generalized and inherited exaggeration in androgen biosynthesis of an inherited nature.

Cortisol secretion from adrenal adenomas discovered as incidentalomas is responsive to ACTH

OBJECTIVE

Adrenal adenomas discovered as incidentalomas may secrete cortisol and cause subclinical hypercortisolism. This cortisol secretion is considered to be autonomous. The aim was to investigate whether cortisol secretion by adenomas is responsive to ACTH.

DESIGN

Descriptive retrospective study of consecutive patients.

PATIENTS

Eighty patients found to have adrenal incidentalomas during 2008 and 2009 at our hospital were examined, and 50 patients with a unilateral adenoma were included in the study.

MEASUREMENTS

Cortisol and ACTH were measured at baseline and using 1-mg overnight dexamethasone suppression test (DST). The cortisol response to ACTH was calculated using the expression: (cortisolbasal -cortisolDST )/(ACTHbasal -ACTHDST ).

RESULTS

The patients were divided into three groups according to their basal ACTH: ≥3·0 pm (29 patients), 2·0-2·9 pm (9 patients) and <2·0 pm (12 patients). Cortisol at DST was similar in the three groups: 30, 46 and 43 nm (P = 0·10). The cortisol response to ACTH increased stepwise between the groups: 98, 172 and 249 nm/pm (P = 0·000, undetectable ACTH was set to 0 pm). Basal ACTH was negatively correlated with the size of the adenoma and positively correlated with the attenuation of the adenoma at unenhanced CT (P = 0·03 and P = 0·04, respectively).

CONCLUSIONS

Patients with adrenal adenomas and low basal ACTH show increased cortisol response to ACTH, and the adenomas seem to be the source of the increased cortisol secretion. The increased response to ACTH could be a pathogenic factor in metabolic complications of subclinical hypercortisolism. The cortisol response to ACTH may therefore be a useful measure of subclinical hypercortisolism.

Cortisol and the polycystic ovary syndrome

Adrenal steroidogenesis is under the control of the hypothalamic-pituitary-adrenal (HPA) axis. Furthermore, metabolic factors including insulin and obesity-related signals may play a role in the regulation of both enzymes involved in the steroidogenetic pathways, as well as in the regulation of the HPA axis. In women with the polycystic ovary syndrome (PCOS), cortisol production rate is probably normal, although adrenal androgens can be overproduced in a subset of affected women. Cortisol metabolism and regeneration from inactive glucocorticoids can also be disrupted in PCOS, thereby contributing to determining an adrenal hyperandrogenic state. Finally, overactivity of the HPA axis may be related to the high prevalence of psychopathological and eating disorders in women with PCOS, implying a maladaptive allostatic load in the adaptive mechanisms to chronic stress exposure.

Cortisol production rate is similarly elevated in obese women with or without the polycystic ovary syndrome

CONTEXT

The pituitary-adrenal axis in obesity and polycystic ovary syndrome (PCOS) is marked by increased urinary excretion of cortisol and its metabolites. It is not as yet clear whether the increased cortisol production in PCOS is related to obesity per se.

INTERVENTION AND METHODS

We investigated 15 obese PCOS women with a body mass index of 30-54 kg/m(2) and 15 healthy obese controls (body mass index 31-60 kg/m(2)) with a regular menstrual cycle. Patients and control women underwent 24-h blood sampling at 20-min intervals. Cortisol concentrations were measured with a sensitive assay. Data were analyzed with a new deconvolution program, approximate entropy, and cosinor regression.

OUTCOME

Basal, pulsatile, and total cortisol production expressed per liter distribution volume, per square meter body surface, and as absolute amount per 24 h was similar in PCOS patients and matched healthy control women. In addition, the regularity of cortisol secretion and the diurnal properties were identical. Compared with 10 lean control women, mean cortisol production per liter distribution volume was similar in the three groups, but the total 24-h cortisol production was increased in obese control women and PCOS women.

CONCLUSION

This study demonstrates equally increased cortisol production in PCOS women and obese healthy control women.

Adrenal androgen production capacity remains high up to menopause in women with polycystic ovary syndrome

INTRODUCTION

Hyperandrogenism is one of the main features of polycystic ovary syndrome (PCOS). Of circulating androgens, 50% of androstenedione and testosterone are of ovarian and adrenal origin, whereas dehydroepiandrosterone (DHEA) and DHEA sulfate are almost uniquely of adrenal origin. Our previous studies have indicated that ovarian androgen production capacity is enhanced in women with PCOS, and it remains high until late reproductive age. To study whether this also applies to adrenal androgen production, ACTH tests were performed in healthy women and in women with PCOS.

MATERIALS

Sixty-nine healthy women (aged 19-62 yr; body mass index 19.2-35.0 kg/m2) and 58 women with previously diagnosed PCOS (aged 18-59 yr; body mass index 19.0-42.9 kg/m2) participated in the study.

METHODS

The subjects underwent ACTH stimulation tests, and serum cortisol, 17-hydroxyprogesterone, androstenedione, testosterone, DHEA, and DHEA sulfate levels were analyzed at 0, 30, and 60 min.

RESULTS

Basal and ACTH-stimulated levels of most adrenal androgens decreased in healthy women with age, whereas in women with PCOS, only the concentrations of basal serum 17-hydroxyprogesterone decreased, and all areas under the curve (AUCs) remained unchanged and significantly higher (except for DHEA) than those in control women. Likewise, at the menopausal transition, pre- and postmenopausal women with PCOS exhibited mainly unchanged and higher basal androgen and AUC levels.

CONCLUSIONS

Similarly to ovarian endocrine function, serum adrenal steroid levels and adrenal steroid production capacity remain enhanced at least up to menopause in women with PCOS.