Gonadotropin responses to gonadotropin-releasing hormone and prolactin responses to thyrotropin-releasing hormone and metoclopramide in women with amenorrhea and insulin-treated diabetes mellitus

Alterations in the Menstrual Cycle as a Peculiar Sign of Type 1 Diabetes Mellitus: A Meta-analytic Approach

BACKGROUND

Menstrual irregularities are present in >30% of women with type 1 diabetes mellitus (T1DM). These abnormalities will likely lead to reduced fertility and earlier menopause. T1DM management has changed over time, with even more emphasis on stringent levels of glycemic management. Thus, we investigated whether therapeutic T1DM changes have an influence on the proportion of menstrual disorders in women with T1DM.

METHODS

A meta-analysis was performed that included clinical trials in which menstrual abnormalities in women with T1DM were studied. The literature was checked for studies in which women with T1DM were compared with healthy, age-matched controls. Case-control, cohort, and cross-sectional studies were included. The primary endpoint was rate of menstrual dysfunction.

RESULTS

Menstrual dysfunction was higher in women with T1DM compared with controls (odds ratio 2.08, 95% confidence interval [CI] 1.43 to 3.03, p<0.001), even when sensitivity analysis was performed, considering only studies published after 2000. The age at menarche was higher for women with T1DM compared with controls (mean difference 0.53, 95% CI 0.32 to 0.74 years, p<0.001). The proportion of menstrual abnormalities in T1DM was inversely related to diabetes duration, but was unrelated to both body mass index and glycated hemoglobin.

CONCLUSIONS

The meta-analytic approach used confirmed the correlation between T1DM and menstrual irregularities. T1DM menstrual dysfunction seemed unrelated to change in therapeutic management across years, as well as to glycemic management and body weight. The underlying pathogenetic mechanisms are not fully understood.

Insulin and Zinc Co-Administration Ameliorate Diabetes Mellitus-Induced Reproductive Dysfunction in Male Rats

Impaired male reproductive function is a major complication associated with diabetes mellitus (DM). Whether or not insulin, when co-administered with zinc will reverse or ameliorate reproductive dysfunction in male diabetics is not known. This study thus sought to establish if co-administration of insulin and zinc reverses or ameliorates male reproductive dysfunction in DM better than either insulin or zinc. Five (5) normal and twenty (20) diabetic sexually mature rats were assigned into five groups of five animals each. Group A consisted of normal rats and had access to only food and water. Group B consisted of diabetic animals with no treatment and served as DM control. Groups C and D consisted of diabetic animals and received insulin and zinc respectively. Group E consisted of diabetic animals and received both insulin and zinc. All diabetic animals had free access to food and water. Insulin in all cases was given subcutaneously twice daily in the morning and evening at 1 unit and 4 units respectively. Zinc (10mg/kg) was given orally once daily. Treatments in all cases commenced two weeks after DM was confirmed. The treatment lasted ten days. Samples were thereafter collected for analyses. DM decreased sperm count, sperm motility, sperm viability, normal sperm cells, semen pH, serum follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone, while increasing sperm cells with defective tails. DM also impaired testicular morphology. Insulin and zinc co-administration improved sperm viability, sertoli cell count, Johnsen's score, serum FSH, LH and testosterone. Co-administration also improved semen pH towards normal. Insulin or zinc ameliorated several aspects of DM-induced male sexual dysfunction. However, the co-administration of insulin and zinc provided better results.

Repression of HDAC5 by acetate restores hypothalamic-pituitary-ovarian function in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) accounts for 90-95 % of worldwide diabetes cases and is primarily characterized by insulin resistance. Its progression as a chronic metabolic disease has been largely associated with female reproductive abnormalities, including ovarian dysfunction with consequent infertility. Epigenetic modifications have been suggested as a possible link to metabolic comorbidities. We therefore hypothesized that short chain fatty acids, acetate (ACA), a potential histone deacetylase inhibitor (HDAC) ameliorates hypothalamic-pituitary-ovarian (HPO) dysfunction in T2DM. Female Wistar rats weighing 160-190 g were allotted into three groups (n = 6/group): Control (vehicle; po), T2D and T2D + ACA (200 mg/kg; po). T2DM was induced by fructose administration (10 %; w/v) for 6 weeks and single dose of streptozotocin (35 mg/kg; ip). The present data showed that in addition to insulin resistance, increased fasting blood glucose and insulin, T2DM induced elevated plasma, hypothalamic and ovarian triglyceride, lipid peroxidation, TNF-α and glutathione depletion. Aside, T2DM also led to increased plasma lactate production and γ-Glutamyl transferase as well as decreased gonadotropins/17β-estradiol. Histologically, hypothalamus, pituitary and ovaries revealed disrupted neuronal cells/moderate hemorrhage, altered morphology/vascular congestions, and degenerated antral follicle/graafian follicle with mild fibrosis and infiltrated inflammatory cells respectively in T2D animals. Interestingly, these alterations were accompanied by elevated plasma/hypothalamic HDAC5 and attenuated when treated with acetate. The present results demonstrate that T2DM induces HPO dysfunction, which is accompanied by elevated circulating/hypothalamic HDAC5. The results in addition suggest that acetate restores HPO function in T2DM by suppression of HDAC5 and enhancement of insulin sensitivity.

Sex-specific differences in insulin resistance in type 1 diabetes: The CACTI cohort

OBJECTIVE

To test the hypothesis that multitissue deficits in insulin sensitivity are greater among women than men with type 1 diabetes compared to respective controls.

RESEARCH DESIGN AND METHODS

Three-stage hyperinsulinemic-euglycemic clamps (4, 8, 40 mU/m2/min) were performed on 41 people with type 1 diabetes and 47 adults without diabetes (mean ± SD age 46 ± 8). Infusions of [1-13C]palmitate, [1,1,2,3,3-2H2]glycerol, and [6,6-2H2]glucose isotope tracers were used to determine free fatty acid (FFA), glycerol, and glucose kinetics in 52 of these participants (25 M and 27 W).

RESULTS

There was no difference in age or BMI by type 1 diabetes status in either sex. Free fatty acid rate of appearance (FFA Ra) was higher in both sexes with type 1 diabetes compared to those without diabetes during stages 1 and 2. The same was seen with glycerol for stages 1 and 2. During stage 3 glucose rate of disappearance (Rd) was lower in those with type 1 diabetes among both sexes. All had sex by type 1 diabetes interactions with greater deficits in insulin sensitivity in women. While there was no sex by diabetes interaction in regards to glucose rate of appearance (Ra), those with type 1 diabetes had a higher glucose Ra than those without diabetes.

CONCLUSIONS

We found that type 1 diabetes affected adipose and skeletal muscle insulin sensitivity to a greater extent in women than in men, perhaps contributing to the greater relative increase in cardiovascular risk in women with type 1 diabetes.

Review: Diabetes and assisted reproductive technology

Patients with a range of medical disorders, including diabetes mellitus, are increasingly seeking access to assisted reproductive technology (ART). With appropriate patient selection, monitoring and counselling, these technologies may be applied successfully. Diabetes in the female is associated with disturbed ovarian function but strict metabolic control may encourage resumption of ovulation and allow ovarian stimulation for ART. Insulin metabolism appears intimately involved with ovarian function, through mechanisms encompassing the actions of insulin-like growth factors, but is not yet fully understood. Diabetes has minimal effects on spermatogenesis but may severely disrupt erectile and/or ejaculatory function; the techniques of epididymal sperm aspiration and intracytoplasmic sperm injection (ICSI) are particularly useful in such cases. Well-controlled diabetes is not associated with recurrent miscarriage but diabetes is a risk factor for pregnancy-induced hypertension and, poorly controlled, is associated with neonatal macrosomia. In reproduction, as in general health, good metabolic control is key to a successful outcome.

Female reproduction and type 1 diabetes: from mechanisms to clinical findings

BACKGROUND

The functional reproductive alterations seen in women with type 1 diabetes (T1D) have changed as therapy has improved. Historically, patients with T1D and insufficient metabolic control exhibited a high prevalence of amenorrhea, hypogonadism and infertility. This paper reviews the impact of diabetes on the reproductive axis of female T1D patients treated with modern insulin therapy, with special attention to the mechanisms by which diabetes disrupts hypothalamic-pituitary-ovarian function, as documented mainly by animal model studies.

METHODS

A comprehensive MEDLINE search of articles published from 1966 to 2012 was performed. Animal model studies on experimental diabetes and human studies on T1D were examined and cross-referenced with terms that referred to different aspects of the gonadotropic axis, gonadotrophins and gonadal steroids.

RESULTS

Recent studies have shown that women with T1D still display delayed puberty and menarche, menstrual irregularities (especially oligomenorrhoea), mild hyperandrogenism, polycystic ovarian syndrome, fewer live born children and possibly earlier menopause. Animal models have helped us to decipher the underlying basis of these conditions and have highlighted the variable contributions of defective leptin, insulin and kisspeptin signalling to the mechanisms of perturbed reproduction in T1D.

CONCLUSIONS

Despite improvements in insulin therapy, T1D patients still suffer many reproductive problems that warrant specific diagnoses and therapeutic management. Similar to other states of metabolic stress, T1D represents a challenge to the correct functioning of the reproductive axis.

Fertility Issues in Women with Diabetes

Diabetes mellitus Type 1 and Type 2 should be considered in the differential diagnosis of menstrual abnormalities and infertility. The reproductive period of diabetic women may be reduced due to delayed menarche and premature menopause. During the reproductive years, diabetes has been associated with menstrual abnormalities, such as oligomenorrhea and secondary amenorrhea. It was found that better glycemic control and prevention of diabetic complications improves these irregularities and increases fertility rates close to those that are seen in the general population. Women with persistent menstrual abnormalities despite adequate treatment need to be approached by broader evaluation, which will include the examination of the hypothalamic–pituitary–ovarian axis and the hormonal status, presence of autoimmune thyroid disease and antiovarian autoantibodies, and hyperandrogenism.

Pituitary-testicular axis function, biological to immunological ratio and charge isoform distribution of pituitary LH in male rats with experimental diabetes

Men with insulinopenic diabetes mellitus frequently present hypogonadism and exhibit circulating luteinizing hormone (LH) molecules with increased biological activity. To further study this latter issue, we analyzed the pattern of isoform distribution and the impact of changes in terminal glycosylation of pituitary LH on the bioactivity of this gonadotropin in experimental diabetes. Adult male rats were treated with streptozotocin or vehicle and euthanized on days 30, 60, or 90 posttreatment. All diabetic groups exhibited a significant decrease in serum insulin and testosterone levels as well as in sperm count; serum gonadotropins and 17beta-estradiol decreased only after 90 days of insulinopenia. Both the immunoreactive concentrations and the biological to immunological ratio of intrapituitary LH significantly increased in all experimental groups, as assessed by an in vitro homologous bioassay in HEK-293 cells expressing a recombinant LH receptor. Chromatofocusing of pituitary extracts revealed the presence of multiple LH charge isoforms; the pH distribution profile of LH in diabetic and control rats was indistinguishable on days 30 and 60 posttreatment. By contrast, the abundance of more basic isoforms (pH 9.99-9.0) decreased and that of isoforms with pH values 8.99-8.0 increased in rats with long-standing diabetes compared to controls. It is concluded that experimental diabetes alters the function of the pituitary-testicular axis, resulting in reduced sex steroids levels and hypogonadotropism. Long-standing insulinopenia leads to a paradoxical accumulation of intrapituitary LH molecules enriched in bioactivity with altered terminal glycosylation, which are apparently subserved by distinct mechanisms involving altered hypothalamic and/or gonadal inputs on the gonadotrope.

Fertility in women with type 1 diabetes: a population-based cohort study in Sweden

OBJECTIVE

The purpose of this study was to assess fertility in women with type 1 diabetes and the risk of congenital malformations in their offspring.

RESEARCH DESIGN AND METHODS

This was a register-based cohort study in Sweden. All 5,978 women hospitalized for type 1 diabetes at age <or=16 years identified in the Swedish Inpatient Register during 1965-2004 were followed until the end of 2004 through linkage to nationwide registers. A standardized fertility ratio (SFR), the ratio of observed to expected number of live births, with 95% CIs, was used to express the relative fertility rate. The proportion of newborns with congenital malformations was compared with that of the general population.

RESULTS

We observed 4,013 live births (SFR 0.80 [95% CI 0.77-0.82]). The SFRs for those who had retinopathy, nephropathy, neuropathy, or cardiovascular complications were 0.63, 0.54, 0.50, and 0.34, respectively. Stratified analyses by year of first hospitalization showed that the reduced fertility was confined to women first hospitalized before 1985, but the presence of complications was associated with subfertility in all calendar-year strata. The proportions of newborns with congenital malformations decreased from 11.7% during 1973-1984 to 6.9% during 1995-2004 but were consistently higher than the corresponding figures for the general population.

CONCLUSIONS

Women with type 1 diabetes have reduced fertility, but it appears that normalization has occurred among women with uncomplicated disease and an onset in the past 20 years. Our results suggest that the stricter metabolic control exercised in the past 20 years may have helped prevent subfertility. However, although the risk of congenital malformations has decreased, it is still higher than that for the general population.

The hypothalamus–pituitary–ovary axis and type 1 diabetes mellitus: a mini review

A high prevalence of menstrual cycle and fertility disturbances has long been associated with diabetes mellitus. However, rationalization of the intrinsic mechanisms of these alterations is controversial and even contradictory. This review considers (i) the relationship between diabetes mellitus, especially type 1 diabetes mellitus (T1DM), and the hypothalamus-pituitary-ovary (HPO) axis, (ii) the state of our knowledge concerning neuroendocrine control and its relationship with dopaminergic and opioid tonus, and (iii) the influence of the hypothalamus-pituitary-adrenal axis on ovarian function. Functional disturbances that occur as a consequence of diabetes are also discussed, but some T1DM-related diseases of autoimmune origin, such as oophoritis, are not further analysed. Although there are clear indications of a relationship between menstrual and fertility alterations and glycaemic control, in many instances the improvement of the latter is not sufficient to reverse such alterations. It appears that the oligoamenorrhoea and amenorrhoea associated with T1DM is mainly of hypothalamic origin (i.e. failure of the GnRH pulse generator) and may be reversible. The importance of the evaluation of the HPO axis in T1DM women with menstrual irregularities, even in the presence of adequate metabolic control, is emphasized.

Impaired fertility caused by endocrine dysfunction in women

Infertility can be frustrating for patients and physicians. Endocrine dysfunction can impair fertility and alter pregnancy outcome. Once the diagnosis is secured, most endocrine disorders are reversible or can be adequately managed to restore fertility and decrease associated pregnancy complications. Improved understanding of the subtleties and intricacies of mechanisms by which endocrinopathies can hinder fertility and influence the course of a pregnancy is vital, more so in the era of assisted reproductive technology, because pregnancy in an abnormal endocrine environment can be disastrous. The role of autoimmunity in infertility and pregnancy loss is less clear; in this context, there are limited management options to improve fertility and overall pregnancy outcomes.

Evaluation of hypothalamic-pituitary-adrenal axis in amenorrhoeic women with insulin-dependent diabetes

Diabetes is associated with a higher incidence of secondary hypogonadotrophic amenorrhoea. In amenorrhoeic women with insulin-dependent diabetes a derangement in hypothalamic-pituitary-ovary axis has been proposed. No data exist on hypothalamic-pituitary-adrenal function in these women. Gonadotrophin releasing hormone (GnRH), corticotrophin releasing hormone (CRH), metoclopramide and thyroid releasing hormone (TRH) tests were performed in 15 diabetic women, eight amenorrhoeic (AD) and seven eumenorrhoeic (ED). Frequent blood samples were taken during 24 h to evaluate cortisol plasma concentrations. There were no differences between the groups in body mass index, duration of diabetes, insulin dose and metabolic control. The AD women had lower plasma concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin, oestradiol, androstenedione and 17-hydroxyprogesterone (17-OHP) than the ED women. The responses of pituitary gonadotrophins to GnRH, and of thyroid stimulating hormone (TSH) to TRH, were similar in both groups. The AD women had a lower prolactin response to TRH and metoclopramide, and lower ACTH and cortisol responses to CRH, than the ED women. Mean cortisol concentrations > 24 h were higher in the amenorrhoeic group. Significant differences in cortisol concentrations from 2400 to 1000 h were found between the two groups. Insulin-dependent diabetes may involve mild chronic hypercortisolism which may affect metabolic control. Stress-induced activation of the hypothalamic-pituitary-adrenal axis would increase hypothalamic secretion of CRH. This would lead directly and perhaps also indirectly by increasing dopaminergic tonus to inhibition of GnRH secretion and hence hypogonadotrophic amenorrhoea. Amenorrhoea associated with metabolically controlled insulin-dependent diabetes is a form of functional hypothalamic amenorrhoea that requires pharmacological and psychological management.

Influence of residual insulin secretion and duration of diabetes mellitus on the control of luteinizing hormone secretion in women

BACKGROUND

The aim of the present study was to establish whether the persistence of residual beta-cell activity after long-term diabetes mellitus (DM) exerts a protective role on luteinizing hormone (LH) secretion.

METHODS

The LH responses to stimulation with gonadotropin-releasing hormone (Gn-RH) (100 microg in an i.v. bolus) or naloxone (4 mg injected in an i.v. bolus, followed by the constant infusion of 8 mg in 2 h) were measured in C-peptide-positive (CpP) and C-peptide-negative (CpN) normally menstruating women with short-term (group 1 < 3 years, CpP n = 11, CpN n = 11) or long-term (group 2 > 10 years, CpP n = 11, CpN n = 11) DM and in age-matched normal control subjects (n = 11).

RESULTS

Gn-RH induced significant increments in LH secretion in all groups. Significant LH responses to naloxone were observed in all groups, except in group 2 CpN patients. However, the LH response to either Gn-RH or naloxone was significantly lower in group 1 CpN, group 2 CpP and group 2 CpN patients than in the normal control subjects. Furthermore, the LH response was significantly lower in group 2 CpP than in group 1 CpP patients and in group 2 CpN than in group 1 CpN subjects.

CONCLUSIONS

These results indicate a role for both deficiency in residual endogenous insulin secretion and duration of diabetes in the derangement of LH secretory control. The data suggest that the protective role exerted by residual beta-cell activity on LH secretion during the early years of DM diminishes with time elapsed after the onset of diabetes mellitus.

Hypothalamic-pituitary axis dysfunction in critically ill patients with a low free thyroxine index

The purpose of this study is to investigate the association of hypothalamic-pituitary axis abnormalities with the free thyroxine index (FTI) in critically ill patients. Fourteen critically ill patients and twenty healthy volunteers were studied using combined anterior pituitary gland testing with CRF, GHRH, TRH, and GnRH. The subjects were grouped as follows: I-healthy volunteers; II-sick/normal FTI; and III-sick/low FTI. Serial measurements of hormones were performed over a two-hour interval and the following parameters were measured: baseline level, response amplitude and time to maximal response. Response velocities and area-under-the-curves (integrated responses) were also computed. Group III had a longer mean ICU duration prior to testing than group II. Urinary cortisol, serum cortisol and serum PRL levels were elevated in groups II and III. However, group III had lower baseline ACTH levels, slower ACTH and TSH response velocities and decreased PRL integrated responses. Cortisol response parameters were similar between groups II and III. There were no differences in LH, FSH or GH response velocities or integrated responses among the 3 groups. These data confirm that critically ill patients develop hyperprolactinemia and hypothalamic-pituitary-adrenal axis activation but when a low FTI exists, a plurality of changes occur reflected by attenuated PRL, TSH and ACTH responses despite unaffected adrenal cortisol output.

Insulin-dependent diabetes mellitus and menstrual dysfunction

Disordered reproductive function has long been recognized as a prevalent problem among women of reproductive age who suffer from insulin-dependent diabetes mellitus (IDDM). Delay in menarchial age is frequently seen if IDDM develops in the peripubertal years and some form of menstrual dysfunction is found in nearly one-third of all women of reproductive age with IDDM. This review summarizes some of the prevailing views regarding the mechanisms through which uncontrolled IDDM is thought to disrupt normal hypothalamic-pituitary-gonadal function. Although animal studies have suggested that poorly controlled IDDM may adversely affect the uterovaginal outflow tract and/or ovarian function, no clinical studies have suggested that abnormal uterine or ovarian function underlies the menstrual dysfunction observed in young diabetic women. Similarly, pituitary function as assessed by basal gonadotrophins and gonadotrophin-releasing hormone (GnRH)-stimulated gonadotrophin release appears to be normal in young women with IDDM. Moreover, although there has been some suggestion that pituitary function may decline with increasing duration of diabetes, this issue has not been thoroughly investigated. It appears that the oligo/amenorrhea noted in IDDM is principally hypothalamic in origin and may represent intermittent (and perhaps reversible) failure of the GnRH pulse generator, similar to the situation observed in women who engage in endurance training or who suffer from anorexia nervosa. Although the exact pathophysiological mechanisms that subserve dysfunction of the GnRH neuronal system are not well understood, attention has focused on increased central opioidergic activity, increased central dopaminergic activity, and central glucose deprivation. In this era of emphasis on tight glycaemic control and its impact in preventing diabetes complications, the consequences of IDDM on reproductive potential appear to be important and must be included in future investigative efforts.

Streptozotocin-induced diabetes blocks the positive feedback release of luteinizing hormone in the female rat

The effects of streptozotocin-induced (STZ) diabetes on the release of gonadotropins was studied in female rats. In the first experiment, rats were ovariectomized and 2 days later were injected with STZ. Three weeks later rats were treated with estrogen and progesterone and blood samples were taken via intraatrial cannulae for luteinizing hormone (LH) assay. Afternoon surges of LH were seen in 4/5 control but 0/8 STZ rats. Pituitary responses to LH-releasing hormone in vitro did not differ. In the 2nd experiment, ovariectomized estrogen-primed rats were killed prior to and during a progesterone-induced LH surge. As in Experiment 1, STZ-treatment inhibited the LH surge but did not effect the afternoon rise in median eminence norepinephrine turnover which has previously been shown to be important in stimulating LH release. Turnover of norepinephrine in the anterior hypothalamus was depressed in the diabetic rats both prior to and during the expected time of the LH surge. Dopamine turnover was depressed in all three brain regions studied. It can be concluded that the positive feedback control of LH release is severely attenuated in diabetic rats but the mechanism explaining the loss is not clear. Diabetes-induced alterations in hypothalamic catecholamine metabolism may be involved but further work is needed to more carefully define these relationships.

The effects of a dopamine antagonist on luteinizing hormone and prolactin release in women with anorexia nervosa and in normal controls

To evaluate the possible role of central dopaminergic suppression of gonadotropin secretion in the genesis of amenorrhea associated with anorexia nervosa (A.N.), a central D-2 dopamine receptor blocker was administered to 10 women with A.N. and 10 regularly menstruating age-matched controls. Serum prolactin and luteinizing hormone (LH) levels were measured at -15, 0, 30, 60, 120, and 180 min after administration of metoclopramide (10 mg orally). Mean basal prolactin (p less than 0.001) and estradiol levels (p less than 0.02) were significantly lower in women with A.N. The prolactin response to metoclopramide was significantly impaired in women with anorexia nervosa. No correlation was found between the prolactin response and percentage ideal body weight. Basal and post-stimulation prolactin levels were correlated with estradiol levels. After adjusting for the effects of estradiol, significant differences between patients with A.N. and controls remained in prolactin levels at baseline (p less than 0.01), 120 min (p less than 0.02) and 180 min (p less than 0.05). Metoclopramide did not induce a significant rise in LH levels in either the A.N. or control groups. These data are consistent with central dopaminergic inhibition of prolactin secretion in anorexia nervosa but do not support the hypothesis that central dopaminergic inhibition is related to diminished LH release in this state.

Hormonal changes in severely uncontrolled type 1 (insulin-dependent) diabetes mellitus

To investigate endocrinological changes associated with severely uncontrolled type 1 (insulin-dependent) diabetes mellitus 27 patients (19 men, eight women) with ketoacidosis or severe ketonuria (= group 1) were examined on admission and after recovery. For comparison 13 non-ketotic patients (seven men, six women), admitted for adjustment of treatment because of poor diabetic control (= group 2), and 20 healthy controls were studied. On admission, the serum testosterone levels in men were lower in group 1 (15.1 +/- 2.0 nmol l-1) (mean +/- SEM) than in group 2 (27.2 +/- 2.8 nmol l-1) (p less than 0.01) and healthy controls (20.6 +/- 2.0 nmol l-1) (p less than 0.05). During treatment the testosterone levels in group 1 rapidly rose to the control level. The serum oestradiol levels in women were low in group 1 both on admission and discharge. The serum prolactin levels were low in female patients in group 1 (119 +/- 17 mIU l-1) compared with the women in group 2 (315 +/- 75 mIU l-1) (p less than 0.05). On admission the serum cortisol levels were higher and their response to 1 mg of dexamethasone was weaker in group 1 than in group 2 and healthy controls. After recovery the serum cortisol levels fell by 15% (p less than 0.01) and the response to 1 mg of dexamethasone returned to normal in group 1. In group 1 during treatment the serum free T4 and reverse T3 levels fell, and the T3 levels rose, whereas the thyroid stimulating hormone (TSH) levels and their responses to TRH remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Luteinizing hormone responses to gonadotropin-releasing hormone and naloxone in menstruating women with type I diabetes of different duration

Luteinizing hormone (LH) responses to gonadotropin-releasing hormone (GnRH) (100 micrograms injected intravenously (IV)) or naloxone (4 mg injected plus 8 mg infused in 2 hours IV) were evaluated in 29 women with insulin-dependent diabetes mellitus (IDDM) (duration, group I (n = 15): less than 10 years, range 3 to 9 years; group II (n = 14): greater than 10 years, range 11 to 20 years) and in 15 normal controls, on the 22nd days of normal menstrual cycles. Both GnRH- and naloxone-induced LH responses were similar in group I diabetics and normal controls, whereas they were significantly lower in group II than in group I diabetics or normal controls. Positive correlations were found between LH responses to GnRH and naloxone, whereas negative correlations were observed between maximal LH peaks in response to GnRH or naloxone and duration of diabetes. These data indicate that a hypothalamic pituitary disorder affects LH secretion with time after the onset of IDDM.

Effects of improved blood glucose on insulin-induced hypoglycaemia, TRH, GnRH and exercise tests in insulin-dependent diabetes

In order to evaluate effects of metabolic control on pituitary function in insulin-dependent diabetes exercise, hypoglycaemia (insulin tolerance test), thyrotrophin releasing hormone and gonadotrophin releasing hormone, tests were performed on 25 patients before (Study 1) and after 2 weeks of improved metabolic control (Study 2). Patients were sub-divided into C-peptide negative (CpN, 10 patients with no residual C-peptide secretion) and C-peptide positive (CpP, 15 patients with residual beta-cell function) groups for analysis of results. Exercise induced higher growth hormone responses in CpN patients independent of metabolic control (P less than 0.001). Thyrotrophin releasing hormone induced higher growth hormone responses in CpN patients; this response was threefold greater after improved control (P less than 0.005). Growth hormone and cortisol response to hypoglycaemia and thyroid stimulating hormone and prolactin secretion in response to thyrotrophin releasing hormone were unaffected by residual beta-cell function or metabolic control. Luteinizing hormone response to gonadotrophin releasing hormone in CpN patients was impaired and lower after improved control (P less than 0.002). The results indicate an association between residual pancreatic insulin secretory and hypothalamic/pituitary function, possibly reflecting central neurosecretion of insulin.

Diabetes mellitus/male infertility

Diabetes mellitus (DM), associated with very subtle disorders, affects, either directly or indirectly, various functions of the reproductive system. Adequate, regular, and timely therapy may prevent or delay these disorders. The T synthesis disorder is caused by molecular changes at the level of Leydig cells and may lead to other disorders in all target organs and tissues. The close correlation between Leydig and Sertoli cells function, i.e., between spermatogenesis and second sex glands function, results in certain anomalies in diabetic patients' spermiograms. Parallel lesions associated with DM, through CNS (hypothalamus-hypophysis), and endocrine profile are indirectly intensified or induced by these disorders, which reflect dysfunction of homeostatic balance in carbohydrate metabolism. Sexual dysfunction in all its forms (reduced erection, impotence, and other libido dissociations) is an accompanying phenomenon of the diabetic disease. However, manifestations of these disorders are related to the regulation of carbohydrate metabolism and to the duration of disease. The duration of disease is not necessarily correlated with sexual dysfunction. Even carbohydrate metabolism remains within normal range in addition to other lesions, diabetes leads gradually but progressively to premature aging of body cells.

The effect of residual beta cell activity on menstruation and the reproductive hormone profile of insulin-dependent diabetics

To investigate the cause of secondary amenorrhoea in insulin-dependent diabetes gonadotrophins, sex steroid hormone levels and residual beta cell activity (C-peptide index) were estimated in a group of 43 women with IDDM. Among 26 women with residual insulin secretion, the C-peptide positive (CpP) group, 5 had secondary amenorrhoea (CpP-Am); among 17 women without endogenous beta cell activity, the C-peptide negative (CpN) group 6 had secondary amenorrhoea (CpN-Am). In this study two different types of secondary amenorrhoea in insulin-dependent diabetics were observed. All CpP-Am women have the classical hormone profile of the polycystic ovary syndrome (increased (LH/FSH ratio, increased serum testosterone, decreased SHBG) together with a history of oligomenorrhoea and excess weight before the onset of diabetes. On the other hand, all CpN-Am women had decreased LH levels as well as low LH/FSH ratio and testosterone levels. These results strongly suggest that a lack of residual pancreatic beta cell activity influences hypothalamus-pituitary function in insulin-dependent diabetes. It might be concluded that PCOS is independent of diabetes while low LH amenorrhoea seems to be the consequence of diabetes and is strongly associated with a lack of residual insulin secretion.

Alterations in carbohydrate metabolism as they apply to reproductive endocrinology

This review has characterized the current state of knowledge of four clinical situations in which an interrelationship of gynecology, endocrinology and carbohydrate metabolism is recognized. The literature contains conflicting descriptions of changes in glucose homeostasis during the menstrual cycle and while using birth control pills. Physiologic changes in receptor number have been demonstrated in each of these situations, so failure to observe differences using glucose tolerance testing may reflect an in vivo homeostatic response to changes in these hormone levels. Thus, in vivo identification of alterations in carbohydrate metabolism induced by endogenous or exogenous steroids may require utilization of models that prevent these homeostatic mechanisms. The association between hyperandrogenism and hyperinsulinism has been better characterized, but the relationship is complicated by the frequent coexistence of obesity. The association may be due to insulin-stimulated ovarian androgen production, and insulin insensitivity may reflect a postreceptor defect. Insulin and its metabolic effects have also been implicated in ovulatory dysfunction in women with diabetes mellitus and identified as a factor affecting all levels of the hypothalamic-pituitary-ovarian axis. A clearer understanding of these relationships and their application to clinical management await further study.

Hypogonadotropic secondary amenorrhea in diabetes: effects of central opiate blockade and improved metabolic control

The effect of improving diabetic control on secondary hypogonadotropic amenorrhea was investigated in patients with insulin-dependent diabetes mellitus (IDDM). Second, the hypothesis that increased central (hypothalamic) opiate inhibition may have been responsible for the suppression of gonadotropin-releasing hormone (GnRH) was tested by observing the effect of a four-hour naloxone infusion (1.4 mg/hour) on serum gonadotropin levels. All known causes of secondary amenorrhea were excluded before patients were eligible for the study. The median duration of amenorrhea was six years, and median body weight was 101 percent of ideal. After six months of improved metabolic control (n = 5) using intensified conventional therapy or continuous subcutaneous insulin infusion, the level of glycosylated hemoglobin dropped from 11.8 +/- 0.9 percent to 8.5 +/- 0.5 percent (p less than 0.005), and body weight increased from 60.5 +/- 1.8 kg to 64.7 +/- 1.4 kg (p less than 0.02). Menses did not, however, return in any patient. There was no significant change in serum levels of estradiol, progesterone, dihydroxyepiandrosterone, testosterone, prolactin, basal or GnRH-stimulated luteinizing hormone, or follicle-stimulating hormone. There was no change in the levels of luteinizing hormone or follicle-stimulating hormone during the naloxone infusion either during poor metabolic control or after six months of improved metabolic control. In conclusion, a form of secondary hypogonadotropic amenorrhea was identified in patients with IDDM that did not remit with sustained improvements in metabolic control. It did not appear to be mediated through increased central opiate tone.

Blunted prolactin response to metoclopramide in insulin-dependent diabetic patients with secondary amenorrhoea

In order to investigate the dopaminergic activity in diabetic women with secondary amenorrhoea we studied the response of prolactin to a dopamine receptor antagonist metoclopramide (MTC - 10 mg i.v.) in three groups of women: 5 insulin-dependent diabetic women with secondary amenorrhoea, 5 insulin-dependent diabetics with normal menstrual cycles and 6 non-diabetic women with regular cycles. Patients with diabetes and secondary amenorrhoea had significantly lower basal LH levels (P less than 0.001) and FSH levels (P less than 0.005) than normally cycling diabetic women. Basal and metoclopramide stimulated prolactin levels were lower in diabetic women with secondary amenorrhoea compared to normally cycling diabetics and control subjects. Evaluation of C-peptide levels in peripheral blood revealed that all amenorrheic diabetics had no endogenous beta cell function while diabetic women with normal cycles (except 1 patient) had preserved residual pancreatic beta cell secretion.

The GABAergic control of prolactin release is not affected by insulin-dependent diabetes mellitus: evidence from studies with sodium valproate

In order to evaluate the influence of the GABAergic system in the regulation of PRL secretion in patients with IDDM, serum PRL levels were measured in 7 diabetics and in 7 normal men with sodium valproate (400 mg per os), a drug capable of increasing cerebral GABA concentrations. A significant decrease of serum PRL concentrations was observed between 30 and 120 min after sodium valproate administration in both control and diabetic subjects. The time course and magnitude of the sodium valproate effect were similar in all subjects. These data confirm the inhibitory control of the GABAergic system on PRL secretion in man as evidenced by the GABAergic drug sodium valproate. It is suggested that this system is not altered in diabetic patients.

Abnormal conjugated dopamine levels in patients with normoprolactinaemic amenorrhoea and in insulin-dependent diabetic patients

We determined the circulating dopamine levels in 17 patients with insulin-dependent diabetes mellitus (IDDM), of whom eight had amenorrhoea (DM-AM) and nine were normally menstruating (DM). Seven non-diabetic women with normoprolactinaemic, normogonadotrophic secondary amenorrhoea (AM) and nine normally menstruating women (controls) were studied. In all subjects basal blood concentrations of free dopamine (f-DA), conjugated dopamine (c-DA), epinephrine (E), norepinephrine (NE), prolactin (PRL), luteinizing hormone (LH), thyroid-stimulating hormone (TSH) and oestradiol-17 beta were determined and all subjects, except for three AM patients, had a Metoclopramide test performed for measurements of f-DA, c-DA, PRL, LH and TSH. Plasma c-DA was significantly (p less than 0.05) increased in patients with amenorrhoea compared to the respective control groups. In diabetic patients c-DA levels were significantly (p less than 0.05) lower compared to controls. The ratio between basal f-DA and c-DA concentrations was significantly (p less than 0.01) higher in diabetic patients compared with non-diabetic patients. After Metoclopramide stimulation DM-AM patients showed a significant (p less than 0.05) rise in c-DA, whereas this was not seen in other groups. DM-AM patients had significantly (p less than 0.05) lower basal PRL and LH levels than DM patients and controls. In addition DM-AM patients had a significantly (p less than 0.05) lower PRL response to Metoclopramide compared with DM patients. There were no significant correlations between catecholamines and basal as well as Metoclopramide stimulated pituitary hormones. This study suggests that the abnormal pituitary hormone secretion in patients with amenorrhoea may in part be caused by an increased dopaminergic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Testicular function and glycemic control in diabetic men. A controlled study

We have investigated testicular function in 28 insulin-dependent diabetic men under the age of 50 years and 119 age-matched controls. Diabetics had reduced testicular volume, semen volume, total and total motile sperm output while plasma LH and FSH levels were elevated. Reduction in semen volume and impotence were more common in long-standing complicated diabetes. Glycosylated hemoglobin (GHb) levels were positively correlated with plasma LH levels (r = 0.46, p less than 0.02) but there was no direct correlation of glycemic control and spermatogenesis. The differences in testicular function were due to decreased spermatogenesis and could not be explained by other forms of testicular pathology or the presence of diabetic neurovascular complications. We conclude that the function of the hypothalamic pituitary testicular axis is impaired in diabetic men, that this impairment is at least partly related to the degree of preceding glycemic control and that multiple levels of the axis may be dysfunctional.

Serum sex hormone concentrations in insulin dependent diabetic women with and without amenorrhoea

Abnormal steroid secretion may contribute to anovulation in insulin dependent diabetic patients with amenorrhoea. We have measured serum sex hormone-binding globulin (SHBG) and free and bound oestrogen and androgen levels in 17 such patients. As controls we included 17 patients with insulin dependent diabetes mellitus and normal menstrual cycles, 21 regularly menstruating normal women (both sampled during early follicular phase), and 23 non-diabetic patients with amenorrhoea. The diabetic patients with normal cycles had significantly higher serum concentrations of delta 4-androstenedione and testosterone than the normal women (P less than 0.01). The amenorrhoeic diabetics in contrast had significantly lower serum concentrations of SHBG, 5 alpha-dihydrotestosterone and free and total oestradiol-17 beta than either group of menstruating women (P less than 0.05), and significantly lower concentrations of delta 4-androstenedione (P less than 0.01), dehydroepiandrosterone sulphate (P less than 0.01), testosterone (P less than 0.01), and oestrone (P less than 0.05), than the cycling diabetics. The two amenorrhoeic groups had similar free and bound sex hormone concentrations except that delta 4-androstenedione levels were significantly lower in the diabetics (P less than 0.01). We conclude that the low sex hormone levels in diabetic women with amenorrhea may be due to suppression of the hypothalamic-pituitary axis in view of the impaired LH secretion found in these patients and that excess androgen secretion seems not to be of aetiological importance in amenorrhea related to diabetes mellitus. The decreased steroid levels in amenorrheic diabetics is due to their suppressed ovarian function while the increased androgen levels in diabetics with regular cycles are probably of ovarian origin.

Gonadotropin secretion before and during acute and chronic dopamine-receptor blockade in insulin-dependent diabetic patients with amenorrhea

The dopaminergic influence on luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin (PRL) was studied in 12 diabetic patients with amenorrhea (DMAM) and in 10 normal menstruating diabetic patients (DM). DMAM patients had a reduction in LH pulsatility (P less than 0.05) and basal LH levels (P less than 0.02), compared with DM patients, whereas they had an LH and FSH response to intravenous metoclopramide (MTC) at 30, 45, and 60 minutes and at 30 minutes, respectively (P less than 0.05). Basal (P less than 0.05) and MTC-stimulated (P less than 0.05) PRL levels were lower in DMAM than in DM patients. Serum PRL and FSH increased significantly (P less than 0.02) in six DMAM patients during 10 weeks of oral MTC administration, whereas no significant (P greater than 0.05) alterations occurred in serum LH and estradiol levels. These data point toward increased dopaminergic activity in DMAM patients.