Plasma androgens and oestradiol during oral glucose tolerance test in patients with polycystic ovaries

Hyperinsulinaemia is common patients with polycystic ovaries (PCO), and a relationship between hyperinsulinaemia and hyperandrogenaemia has been suggested. We studied the effect of increased circulating insulin in response to an oral glucose tolerance test (OGTT) on plasma levels of androgens and oestradiol in PCO patients and in healthy control subjects. A 75 g, 3 h oral glucose tolerance test (OGTT) was performed in eight non-obese and seven obese PCO patients, and in 10 non-obese control subjects. An additional group of five women were fasting during the study period. The increase in insulin concentration was higher in obese and non-obese PCO patients than in non-obese control subjects, and the peak values were observed at 30 or 60 min. In the fasting control subjects, the mean concentration of androstenedione decreased slightly due to a diurnal variation. During the OGTT, mean concentrations of androstenedione decreased in all groups at 30 min, after which a slight increase was observed in PCO patients and a plateau in control subjects. Similarly, mean testosterone increased after an initial decrease in obese PCO patients whereas no change was found in non-obese PCO patients. No statistically significant differences were found in the responses of androstenedione or testosterone levels to OGTT in obese or non-obese PCO patients compared to normals. No significant responses of plasma oestradiol levels to OGTT were found. These findings failed to demonstrate any significantly abnormal acute androgen responses to OGTT-stimulated hyperinsulinaemia in PCO patients, but did not exclude possible long-term effects of hyperinsulinaemia.     

Effect of antagonists of dopamine and opiates on the basal and GnRH-induced secretion of luteinizing hormone, follicle stimulating hormone and prolactin during lactational amenorrhoea in breastfeeding women

The role of dopamine and opiates in the suckling-induced suppressionof gonadotrophin secretion and prolactin release was investigatedduring lactational amenorrhoea in fully breastfeeding womenat 12 weeks post-partum. A total of 26 women, 20 using non-steroidalmethods of contraception and six using the progestogen-onlypill, Noriday (POP), breastfed their babies on demand at a frequencyof 3.6 ± 0.2 suckling episodes during the 8 h study periodwhile blood samples were collected at 10-min intervals. Fivehours after the start of sampling six women were given the dopamineantagonist metoclopramide (10 mg, i.m.) while four women receivedsaline. In a second experiment, six women using nonsteroidalcontraception and three women on the POP received an i.v. infusionof the opiate antagonist naloxone (1.6 mg/h) for 2 h, whilefour women using non-steroidal contraception and three womenon the POP were infused with saline. Two hours after the i.m.injection or start of infusion all women were given an i.v.injection of 10 µg gonadotrophin releasing hormone (GnRH)and samples were collected for a further 1 h. All samples wereassayed for luteinizing hormone (LH), follicle stimulating hormone(FSH) and prolactin. Plasma concentrations of oestradiol were<60 pmol/l in all women and they remained amenorrhoeic forat least 10 weeks after the study. Pulsatile release of LH wasonly observed over the 5 h pre-treatment period in 10 of the20 non-steroid taking women (1–3 pulses/5 h), and in oneof the six women (1 pulse/5 h) on POP. Treatment with metoclopramidecaused a substantial (29-fold) increase in prolactin over baseline,7.4 times the maximum released in response to suckling. Therewas no effect of metoclopramide on the pattern of release ofLH or FSH or the response to GnRH. Infusion of naloxone in womenusing either non-steroidal contraceptives or progestogen-onlypill did not affect prolactin release. Naloxone infusion didnot affect LH or FSH in women using nonsteroidal contraceptives,but caused a small but significant (P < 0.05) increase inboth LH and FSH in women taking the progestogen-only pill. Therewas a significantly greater release of LH and FSH after GnRHin all women after naloxone infusion. These results in breastfeedingwomen during lactational amenorrhoea confirmed that sucklingsuppresses the pulsatile release of LH but not through a dopaminergicpathway, showed that prolactin remains under dopaminergic controlduring human lactation, but suckling does not appear to affectprolactin secretion via an opiate pathway and indicated onlya minor, if any, role for opiates in the sucklinginduced suppressionof GnRH/gonadotrophin secretion but a potential, previouslyunreported, effect of opiates in reducing pituitary responsivenessto GnRH.     

Endocrinology: Insulin hypersecretion together with high luteinizing hormone concentration augments androgen secretion in oral glucose tolerance test in women with polycystic ovarian disease

Female hyperandrogenism is often associated with hyper-insulinaemiaand insulin resistance. We evaluated the hormone responses inan oral glucose tolerance test to investigate the interactionsof gonadotrophins, insulin, C-peptide and androgens in womenwith polycystic ovarian disease (PCOD). In 28 patients withultrasonographically diagnosed PCOD, hyperinsulinaemia and insulinresistance were mainly associated with obesity. Both basal andcumulative sum of insulin to C-peptide ratios were high in obesesubjects, suggesting decreasing hepatic removal of insulin causedby obesity. Nevertheless, in some lean PCOD women, despite normalfasting insulin concentrations, insulin hyper-secretion existed.The mean concentration of testosterone decreased significantlyduring the oral glucose tolerance test both in PCOD and controlwomen, and of androstenedione in the PCOD patients only. However,an increase in androgen responses was found in a subgroup ofPCOD patients, who had both elevated luteinizing hormone (LH)concentrations and hyperinsulinaemic response to oral glucose.In the remaining PCOD patients an inverse correlation betweenLH and insulin was found. The patients with hyperinsulinaemiatogether with LH hypersecretion may represent a subgroup ofPCOD with deranged regulation of androgen secretion.     

Use of naloxone in septic shock

Experimental and clinical evidence show that endogenous opiates (endorphins) contribute to the pathophysiology of circulatory shock. The authors evaluated the effectiveness and safety of continuous infusion of naloxone in five septic patients with prolonged hypotension unresponsive to volume replacement and dopamine infusion. Naloxone (2 mg bolus) was intravenously administered and continued at 0.25 mg/hr for 24 to 48 hours. All five patients had significant increase in mean arterial pressure of between 20 and 30 mmHg (P less than 0.0012). Cardiac index, systemic vascular resistance, and pulmonary arterial pressure were not significantly altered; however, there was a significant difference in pulmonary capillary wedge pressure (P less than 0.034) and urinary output (P less than 0.0273). Subjects did not experience side effects with naloxone. We conclude that continuous infusion of naloxone can reverse endorphin-mediated hypotension in septic shock patients.     

Endocrine and metabolic effects of octreotide, a somatostatin analogue, in lean PCOS patients with either hyperinsulinaemia or lean normoinsulinaemia

The effects on insulin secretion and on the glycaemic and androgen status before and after short-term treatment with octreotide were evaluated in 16 normal weight patients with polycystic ovarian syndrome (PCOS). Hyperinsulinaemia was determined by measuring the insulin response after oral glucose tolerance test (OGTT). Seven patients (group A) were classified as normoinsulinaemic, while nine patients (group B) were considered hyperinsulinaemic according to insulin response after OGTT. Octreotide treatment did not modify either glycaemic or insulinaemic response after OGTT, or androgen profile, in normoinsulinaemic patients. On the contrary, a significant decrease in the basal concentrations of luteinizing hormone (LH), testosterone and androstenedione, and a significant increase in serum concentrations of sex hormone-binding globulin (SHBG) were observed in the hyperinsulinaemic group of patients, in which we observed also a significant decrease of insulinaemic response and a decompensation of the glycaemic profile after OGTT. Our study is the first report showing that: (i) octreotide does not appear to significantly influence pituitary release of gonadotrophins in this group of PCOS patients; (ii) octreotide is able to reduce insulin release, LH and androgen concentrations in lean PCOS patients with hyperinsulinaemia. Due to the presence of a decompensation of glucose homeostasis during treatment, octreotide does not seem advisable for long-term therapy of hyperandrogenism in lean PCOS patients with hyperinsulinaemia.     

Failure of naloxone to reduce the clonidine induced reduction of blood pressure and plasma noradrenaline in patients with essential hypertension

Studies in animals and man indicate a functional interaction between the adrenergic and the opiate systems. In the present study the effect of the opiate receptor blocker naloxone on the reduction of blood pressure and plasma noradrenaline induced by the alpha 2-agonist clonidine was investigated in nine patients with essential hypertension. In a randomised manner the patients received a bolus dose of naloxone (10 micrograms/kg) or physiological saline followed by a slow infusion of naloxone (5 micrograms/kg/h) or saline, respectively. Fifteen minutes after the respective bolus dose, clonidine (3 micrograms/kg) was infused over 10 minutes. Naloxone had no effect on the clonidine induced hypotension and reduction of plasma noradrenaline. Accordingly, there is no evidence that the clonidine induced reduction of blood pressure and plasma noradrenaline involves opiate receptors that can be blocked by naloxone. Plasma adrenaline increased significantly during the early phase of naloxone infusion.     

Cholinergic actions f false neurotransmitters: acetylpyrrolidinecholine

Changes in hippocampal CA1 field potentials during and after tetanic stimulation were studied in rats pretreated with 5 mg/kg s.c. naloxone or saline. Stimuli consisted of successive tetani of increasing frequency; responses at threshold, midrange and asymptotic intensities were sampled. A several fold increase in response amplitude occurred during low frequency stimulation, with no significant differences between the groups. Post-tetanic responses showed depression at the lower frequencies but increases ranging up to 400% at higher frequencies, with the greatest potentiation at threshold; again there were no significant differences between naloxone and saline groups, suggesting that endogenous opiates are not involved.     

Impact of overnight dexamethasone suppression on the adrenal androgen response to an oral glucose tolerance test in women with and without polycystic ovary syndrome

In order to test the hypothesis that adrenocortical overactivity, possibly related to the stress of testing, may impact on the measurement of circulating androgen concentrations during glucose- induced hyperinsulinaemia, we prospectively screened 10 patients with the polycystic ovary syndrome (PCOS) and nine healthy control women with an oral glucose tolerance test (OGTT), before and after the administration of dexamethasone. Blood sampling was performed at 0, 30, 60, 90, and 120 min following the oral ingestion of 75 g of glucose, before and after the administration of 1.0 mg dexamethasone on the evening prior to testing. Total and free testosterone, androstenedione, dehydroepiandrosterone (DHEA), DHEA sulphate (DHEAS), cortisol, glucose and insulin were assessed during the 2 h OGTT. Women with PCOS had increased basal concentrations of free testosterone, total testosterone, androstenedione, and insulin compared to control women. In women with PCOS an acute decline in circulating concentrations of DHEAS occurred during the OGTT. In PCOS women there were no changes in other ovarian or adrenal androgens during OGTT before or following dexamethasone administration. In control women DHEA concentrations declined during the OGTT. Following overnight dexamethasone suppression in control women, circulating concentrations of DHEAS and testosterone also declined. It is concluded that: (i) in PCOS women only the concentration of circulating DHEAS decreased during glucose-induced hyperinsulinaemia and dexamethasone administration did not further alter androgen responses to an OGTT; (ii) it is possible that, in these hyperandrogenic patients, the insulin-related suppression of adrenocortical testosterone and DHEA is negated by their much greater ovarian secretion of these androgens; (iii) in control women DHEA concentrations acutely declined during the OGTT and the administration of dexamethasone resulted in the acute decline of DHEA, DHEAS, and testosterone; (iv) it appears that the stress related to testing impacts on the androgen response to OGTT, at least in healthy women.      

A randomized, controlled trial of methylprednisolone or naloxone in the treatment of acute spinal-cord injury. Results of the Second National Acute Spinal Cord Injury Study

Studies in animals indicate that methylprednisolone and naloxone are both potentially beneficial in acute spinal-cord injury, but whether any treatment is clinically effective remains uncertain. We evaluated the efficacy and safety of methylprednisolone and naloxone in a multicenter randomized, double-blind, placebo-controlled trial in patients with acute spinal-cord injury, 95 percent of whom were treated within 14 hours of injury. Methylprednisolone was given to 162 patients as a bolus of 30 mg per kilogram of body weight, followed by infusion at 5.4 mg per kilogram per hour for 23 hours. Naloxone was given to 154 patients as a bolus of 5.4 mg per kilogram, followed by infusion at 4.0 mg per kilogram per hour for 23 hours. Placebos were given to 171 patients by bolus and infusion. Motor and sensory functions were assessed by systematic neurological examination on admission and six weeks and six months after injury. After six months the patients who were treated with methylprednisolone within eight hours of their injury had significant improvement as compared with those given placebo in motor function (neurologic change scores of 16.0 and 11.2, respectively; P = 0.03) and sensation to pinprick (change scores of 11.4 and 6.6; P = 0.02) and touch (change scores, 8.9 and 4.3; P = 0.03). Benefit from methylprednisolone was seen in patients whose injuries were initially evaluated as neurologically complete, as well as in those believed to have incomplete lesions. The patients treated with naloxone, or with methylprednisolone more than eight hours after their injury, did not differ in their neurologic outcomes from those given placebo. Mortality and major morbidity were similar in all three groups. We conclude that in patients with acute spinal-cord injury, treatment with methylprednisolone in the dose used in this study improves neurologic recovery when the medication is given in the first eight hours. We also conclude that treatment with naloxone in the dose used in this study does not improve neurologic recovery after acute spinal-cord injury.     

Acute insulin response to intravenous glucagon in polycystic ovary syndrome

In order to evaluate the acute insulin response after i.v. injection of glucagon in polycystic ovary syndrome (PCOS), 35 women affected by PCOS and 11 normo-ovulatory controls underwent a 75 g oral glucose tolerance test (OGTT) and, 2 days later, a glucagon test (1 mg i.v.). Patients were analysed according to their degree of obesity; the insulin release after glucagon injection for lean PCOS subjects and control women was not statistically significantly different. Conversely obese PCOS patients had higher insulin secretion after both i.v. glucagon and OGTT when compared to the other groups. Moreover the insulin secretory patterns were heterogeneously represented in lean and obese PCOS women. When the patients were analysed according to their insulinaemic response to OGTT, normoinsulinaemic PCOS women and control subjects had a similar insulin response to i.v. glucagon whereas the hyperinsulinaemic PCOS group had a higher insulin response (P < 0.0001). Moreover, a highly significant relationship was found between the insulin response to OGTT and to glucagon administration in the PCOS population (P < 0.0001; r = 0.73), which was maintained also after controlling for obesity. Our results are consistent with the hypothesis that PCOS patients could have an insulin hyper-response to glucagon administration, that is partially independent from obesity and related to their insulinaemic status. Moreover, the glucagon test could represent an effective alternative to OGTT in screening insulin disorders of PCOS patients (at least in the absence of other risk factors), due to its reliability, simplicity, and speed of performance.      

Effects of naloxone and chlordiazepoxide on lateral hypothalamic self-stimulation in rats

Lateral hypothalamic self-stimulation behavior of rats in an operant chamber was investigated under the treatments of the first injection of naloxone (5 mg/kg) or saline followed by the second injection of chlordiazepoxide (4 mg/kg) or saline. Both inhibitory effect of naloxone and facilitatory effect of chlordiazepoxide on self-stimulation response were statistically significant, but the interaction between the two effects was not obtained. The results indicate that the facilitatory effect of chlordiazepoxide upon self-stimulation is independent of endogenous opioid system. Further, the obtained effect of naloxone was discussed in terms of interaction of the drug with aversive, rather than rewarding, component of self-stimulation.     

The effects of naloxone on cerebral function in spontaneously hypertensive rats during hypotensive haemorrhage

The purpose of this study was to examine the effects of naloxone on signs of relative cerebral ischaemia induced by hypotensive haemorrhage. Mean arterial blood pressure (MAP), heart rate (HR), renal sympathetic nerve activity (rSNA) and somatosensory evoked potentials (SEP) were recorded in chloralose-anaesthetized spontaneously hypertensive rats exposed to graded bleeding. Hypotensive haemorrhage resulted, after a very brief sympathetic excitation, in marked sympathetic inhibition and bradycardia and a considerable reduction of SEP, indicating relative cerebral ischaemia. However, after 25-30 min this sympatho-inhibitory response was reversed to pronounced sympathetic excitation and tachycardia, which was accompanied by a further attenuation of SEP. A single bolus of naloxone (10 mg kg-1) caused transient sympathetic inhibition and bradycardia, which was accompanied by an improvement of SEP. A bolus injection (5-10 mg kg-1) followed by a 30 min infusion of naloxone (25-35 mg kg-1 h-1) caused a sustained SEP improvement despite the fact that MAP was kept constant during naloxone administration. We conclude that naloxone can have beneficial effects on brain function during cerebral ischaemia, effects that are probably due to blockade of opioid receptors. Our model of relative cerebral ischaemia might be useful for evaluating the mechanisms behind the naloxone effects during this condition.     

Endogenous opioids mediate basal hedonic tone independent of dopamine D-1 or D-2 receptor activation

Exogenously administered opiates are recognized as rewarding and the involvement of dopamine systems in mediating their apparent pleasurable effects is contentious. The aversive response to naloxone administration observed in animal studies suggests the presence of an endogenous opioid tone regulating hedonic state. We sought evidence for the requirement for dopamine systems in mediating this action of endogenous opioids by determining whether mice deficient in dopamine D-1 or D-2 receptors were able to display conditioned place aversion to naloxone. Mice received saline in the morning in one chamber and either saline or naloxone (10 mg/kg, s.c.) in the afternoon in another chamber, each day for 3 days. On the test day they were given free access to the testing chambers in the afternoon. Similar to their wild-type littermates, D-1 and D-2 receptor knockout mice receiving naloxone in the afternoon spent significantly less time on the test day in the compartment in which they previously received naloxone, compared with animals receiving saline in the afternoon. The persistence of naloxone-conditioned place aversion in D-1 and D-2 knockout mice suggests that endogenous opioid peptides maintain a basal level of positive affect that is not dependent on downstream activation of dopamine systems involving D-1 or D-2 receptors.     

Effects of naloxone on cardiovascular responses to static exercise and behavior in conscious cats

Conscious cats performing static (isometric) exercise were studied before and after administration of the opiate antagonist naloxone in order to evaluate the possible role of endogenous opiates in regulating cardiovascular responses to static exercise. Intravenous administration (0.4 mg/kg) of naloxone had no effect on resting left ventricular systolic pressure or on heart rate. In addition, similar increases in left ventricular systolic pressure and heart rate occurred during static exercise both before and after naloxone. However, naloxone reduced the number of exercise events the cats would perform per day. We conclude that moderate doses of naloxone do not modulate the cardiovascular responses to moderate static exercise in conscious cats. The results do indicate that endogenous opiates are involved in regulating the number of exercise bouts the cats will perform per day.     

Naloxone does not influence a pyrogen fever in rabbits

Rabbits were made febrile by an intravenous injection of homologous endogenous pyrogen (Interleukin 1). When naloxone (0.1 mg/kg i.v.) followed by 0.06 mg (kg·hr)^–1 infusion) was given at the same time as the pyrogen, the resulting fever was indistinguishable from that following pyrogen alone. It appears unlikely that opioid receptors which are blocked by naloxone play any important part in the fever process.     

Opioid involvement in the perception of pain due to endurance exercise in trained man

The purpose of this study was to evaluate the role of endogenous opiates in modulating physical performance during dynamic exercise in conscious man. The plasma concentration of beta-endorphin (BEP) and of adrenocorticotropic hormone (ACTH) along with muscle pain (McGuill Pain Questionnaire) were assessed in 17 trained, male runners before and after running the longest possible distance within 12 min (i.e., the Cooper test). Each runner participated twice in the test (double-blind cross-over design), with a 1-week interval--with or without an injection of the opiate antagonist naloxone (0.8 mg i.v.). The average (SEM) distance reached was 3,198 (45) m in the naloxone test and 3,240 (38) m in the placebo test. The BEP increased significantly during the tests by a factor of 4.1 on naloxone and by 2.8 on placebo (from the normal resting averages of 1.7 and 2.1 pmol/l, respectively). The ACTH also increased significantly by a factor of 2.0 on naloxone and 2.5 on placebo (from the normal resting averages of 19.3 and 16.8 pmol/l, respectively). There were no significant differences between the naloxone and the placebo test with respect to the increments of BEP or ACTH by exercise. However, the perception of muscle pain was enhanced with naloxone. The increased perception of pain did not decrease the athletes ability to perform in terms of the distance run. We conclude that endogenous opiates are involved in the perception of pain associated with exhaustive exercise and may subserve psychological rather than physiological functions during exercise.     

fMRI measurement of CNS responses to naloxone infusion and subsequent mild noxious thermal stimuli in healthy volunteers

The aims of this study were to assess the effects of a µ-opioid antagonist, naloxone, on endogenous opioid systems and to evaluate the effect of naloxone on the CNS response to mild noxious heat. Doubled-blinded experiments were performed in a cross-over design in 10 healthy male volunteers. Functional magnetic resonance imaging (fMRI) data were collected before and during the infusion and also during thermal stimuli. Increased signal was observed in a number of cortical and subcortical brain regions for naloxone versus saline infusion. Cortical activation was induced in regions including cingulate, prefrontal cortex, and insula. Subcortical regions showing increased signal change included hippocampus and entorhinal cortex. A 46°C stimulus delivered to the back of the hand induced an overall increase in activation in a number of regions in the naloxone group that were not seen in the saline group (e.g., insula, orbitofrontal cortex, thalamus, and hippocampus). These results show that naloxone, even in the absence of psychophysical effects, produces activation in several brain regions that are known to have high levels of µ-opioid receptors and may be involved in endogenous analgesia. Our study is an example of how fMRI can measure subtle changes in brain activation induced by pharmacological agents without cognitive effects.     

Human models of low-grade inflammation: bolus versus continuous infusion of endotoxin

Systemic low-grade inflammation is recognized in an increasing number of chronic diseases. With the aim of establishing an experimental human in vivo model of systemic low-grade inflammation, we measured circulating inflammatory mediators after intravenous administration of Escherichia coli endotoxin (0.3 ng/kg of body weight) either as a bolus injection or as a 4-h continuous intravenous infusion, as well as after saline administration, in 10 healthy male subjects on three separate study days. Only bolus endotoxin caused an increase in heart rate, whereas a slight increase in rectal temperature was observed in both endotoxin groups. Tumor necrosis factor alpha (TNF-alpha), interleukin-6, and neutrophil responses were earlier and more pronounced in the bolus trial compared with the infusion trial results, whereas lymphocytes increased after endotoxin bolus injection as well as infusion without any difference between groups. Finally, endotoxin activated the hypothalamo-pituitary-adrenal axis slightly earlier in the bolus compared to the infusion trial. The continuous endotoxin infusion model may be more representative of human low-grade inflammation than the bolus injection model due to a less dynamic and more sustained increase in circulating levels of inflammatory mediators over time. In conclusion, low-dose endotoxin infusion elicits an inflammatory response, as assessed by a rise in TNF-alpha, and the responses are significantly different according to whether low-dose endotoxin is applied as a bolus injection or as a continuous infusion.     

早期胰岛素泵注对脓毒症大鼠肝损害的影响

目的探讨早期胰岛素泵注对脂多糖（LPS）致大鼠脓毒症模型肝损害的保护作用。方法24只SD大鼠随机分为LPS＋生理盐水组、LPS＋胰岛素组和生理盐水对照组,各组均为8只。各组大鼠在实验前1d行右颈外静脉置管术。LPS＋生理盐水组腹腔注射LPS10mg·kg^-1,同时持续静脉泵注生理盐水1mL·h^-1;LPS＋胰岛素组腹腔注射LPS10mg·kg^-1,同时持续静脉泵注胰岛素生理盐水溶液1mL·h^-1（胰岛素用量为0．25U·kg^-1·h^-1）。生理盐水对照组腹腔注射生理盐水10mg·kg^-1,同时持续静脉泵注生理盐水1mL·h^-1。测定各组腹腔注射LPS或生理盐水前和注射后2、6、12、24h的血糖水平,检测各组腹腔注射LPS或生理盐水后2、6h的血清TNF-α、IL-6水平及24h的血清ALT和AST水平,并观察各组腹腔注射LPS或生理盐水后24h的肝脏组织病理学改变。结果LPS＋生理盐水组在腹腔注射LPS后各采样时间点,血糖水平较生理盐水对照组均显著升高（P〈0．05）。注射LPS或生理盐水后2和6h,LPS＋生理盐水组血清TNF-α和IL-6水平显著高于生理盐水对照组（P〈0．05）。注射LPS或生理盐水后24h,LPS＋生理盐水组血清ALT和AST水平均较生理盐水对照组显著升高（P〈0．05）。LPS＋胰岛素组注射LPS后各采样时间点血糖、TNF-α、IL-6、ALT及AST水平均显著低于LPS＋生理盐水组（P〈0．05）,LPS＋生理盐水组肝脏病理学检查示局灶性肝细胞坏死,炎性细胞浸润,小叶间静脉充血扩张;LPS＋胰岛素组肝脏病理学改变较LPS＋生理盐水组明显减轻。结论早期胰岛素静脉泵注可通过抗炎和降低应激性高血糖作用减轻LPS诱导的肝损害。     

Insulin sensitivity, insulin secretion, and metabolic and hormonal parameters in healthy women and women with polycystic ovarian syndrome

To study the contributions of body mass, body fat distribution and family history of type 2 diabetes mellitus to hyperinsulinaemia, insulin secretion and resistance in polycystic ovarian syndrome (PCOS), 17 lean (LC) and 17 obese (OC) healthy control subjects, and 15 lean (LPCOS) and 28 obese (OPCOS) women with PCOS were investigated. Waist:hip ratio (WHR), serum concentrations of sex steroids, glucose and insulin during a 75 g oral glucose tolerance test (OGTT), and insulin and C-peptide early phase secretion, and insulin sensitivity index using a euglycaemic hyperinsulinaemic clamp were assessed. The PCOS subjects had a higher mean WHR than the controls. A trend towards hyperinsulinaemia and impairment of insulin sensitivity (including the rates of both glucose oxidation and non-oxidation) was observed in LPCOS subjects, but only in OPCOS subjects were these changes significant. Early phase insulin secretion but not the early phase C-peptide secretion was increased in PCOS subjects compared to controls, suggesting that peripheral hyperinsulinaemia in PCOS women was mainly due to the observed lowered hepatic insulin extraction and insulin resistance in skeletal muscle. Moreover, the presence of a family history of type 2 diabetes did not affect early phase insulin or C-peptide secretion in the PCOS group. These results confirm and strengthen earlier contentions, that insulin resistance is a characteristic defect in PCOS and is worsened particularly by abdominal obesity.