ABSTRACT
STUDY QUESTION: Is the functional ovarian reserve in transgender men affected by testosterone therapy? SUMMARY ANSWER: Serum anti-Müllerian Hormone (AMH) levels slightly decrease during testosterone treatment but remain within the normal range, suggesting preserved follicular ovarian reserve. WHAT IS KNOWN ALREADY: Few small studies have investigated the impact of gender-affirming treatment on reproduction in transgender men. Conflicting results were reached concerning ovarian morphology and AMH levels in this context. STUDY DESIGN, SIZE, DURATION: The study consisted of two arms. The first arm was a prospective pilot study, which enrolled 56 transgender men (median age 22.5 [interquartile range (IQR)-19-27.7] years), 27 of whom had polycystic ovary syndrome (PCOS), prior to the initiation of gender-affirming testosterone therapy. A structured assessment was conducted prior to, and at 3 and 12 months after treatment initiation. The second arm was a cross-sectional study that comprised 47 transgender men (median age 24 [IQR-20-31] years) who received testosterone for a median duration of 35 [IQR 13-62] months. The main outcome measures were serum AMH and antral follicle count (AFC) as indices of ovarian follicular reserve. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study was conducted at a tertiary center for transgender health. Gender-affirming therapy was administered according to standard practice. AFC was determined by pelvic (abdominal or transvaginal) ultrasound and blood collection for measurements of AMH, testosterone, estradiol, LH and FSH was performed at the designated time-points. MAIN RESULTS AND THE ROLE OF CHANCE: Prospective arm for the entire group we observed a decrease of 0.71 ng/ml in AMH levels between baseline and 12 months (P = 0.01). When expressed in age-specific percentiles, AMH went from the 47.37th to the 40.25th percentile at 12 months (P < 0.001). In a sub-group analysis, a decline of 9.52 points in age-specific percentile was seen in subjects with PCOS (P < 0.001), while no changes were detected in the non-PCOS group. Testosterone treatment did not affect AFC over time in the entire cohort. In the sub-group analysis, a mean decrease of 5.0 follicles was detected between baseline and the 12 months assessment (P = 0.047) only in subjects with PCOS. In the cross-sectional study, AMH inversely correlated with age but not with treatment duration. Notably AMH did not deviate from the 50th age-specific percentile. Finally, four men fathered biological children after being under testosterone treatment for up to 12 years. LIMITATIONS, REASONS FOR CAUTION: The limited sample size of the pilot study should be kept in mind. An additional limitation is the lack of a control group in the prospective study, as each participant served as his own control. Also, roughly 40% of the ultrasound examinations were performed transabdominally, potentially affecting the accuracy of the AFC measurements.As study participants were quite young, our reassuring data may not apply to older transgender men, either because of an age-related decline in ovarian reserve or to possible long-term effects of testosterone therapy. Furthermore, the chances for fertility preservation may be more limited in subjects with PCOS. WIDER IMPLICATIONS OF THE FINDINGS: This is an additional contribution to the emerging evidence that prolonged testosterone treatment may not be a major obstacle to later fertility potential in transgender men desirous of having children. Larger confirmatory studies, and particularly more with reproductive outcome data, are needed for evidence-based fertility counseling prior to treatment initiation in these subjects. STUDY FUNDING/COMPETING INTEREST(S): This study received no funding. The authors have no competing interests to declare. TRIAL REGISTRATION NUMBER: N/A.
Subject(s)
Ovarian Reserve , Transgender Persons , Adult , Anti-Mullerian Hormone/analysis , Child, Preschool , Cross-Sectional Studies , Female , Humans , Ovarian Follicle , Pilot Projects , Prospective Studies , Testosterone/therapeutic use , Young AdultABSTRACT
We report on a case of a man with familial, X-linked, partial androgen insensitivity, in whom a new point mutation in the androgen receptor (AR) ligand-binding domain (causing a valine-to-alanine substitution at codon 686) was identified. High-dose prolonged testosterone therapy resulted in marked progression in patient's appearance and great improvement in sperm count and characteristics. In combination with intracytoplasmic microinjection, treatment resulted in fertility. This is believed to be the first report of such a case. This case supports high-dose testosterone therapeutic trial in this condition. Furthermore, it underscores the possibility of achieving fertility with current endocrine and assisted reproduction modalities, making some of these X-linked AR mutations paternally transmissible.
Subject(s)
Androgen-Insensitivity Syndrome/drug therapy , Androgen-Insensitivity Syndrome/genetics , Point Mutation , Receptors, Androgen/genetics , Testosterone/therapeutic use , Adult , Amino Acid Substitution , Androgen-Insensitivity Syndrome/pathology , Female , Humans , Infant, Newborn , Infertility, Male/genetics , Infertility, Male/pathology , Infertility, Male/therapy , Male , Pregnancy , Semen Analysis , Sperm Count , Sperm Injections, Intracytoplasmic , Testosterone/administration & dosageABSTRACT
Metabolic syndrome (MS) is comprised of a cluster of abnormalities in glucose, lipid, and vascular homeostasis, which is most commonly linked to abdominal obesity. MS heralds increased risk for development of diabetes and is linked to impairment in insulin signaling. Insulin-degrading enzyme (IDE) is one of the mechanisms through which insulin blood levels are maintained. It has been previously suggested that controlling IDE levels could provide yet another potential therapeutic approach in diabetes. Here we aim to investigate whether changes in serum IDE levels correlate with the severity of MS. Using a highly sensitive ELISA assay of active IDE in human serum, we found a strong correlation between circulating IDE levels and circulating levels of triglycerides, insulin, and c-peptide and an inverse correlation with HDL cholesterol (HDLc). Serum IDE levels were higher in MS subjects than in control subjects. Hence, circulating IDE may serve as a tool to identify subjects with abnormal insulin metabolism, possibly those with MS that are at risk to develop diabetes.
Subject(s)
Insulysin , Metabolic Syndrome , C-Peptide , Glucose Tolerance Test , Humans , InsulinABSTRACT
PPARalpha is a ligand-dependent transcription factor expressed at high levels in the liver. Its activation by the drug gemfibrozil reduces clinical events in humans with established atherosclerosis, but the underlying mechanisms are incompletely defined. To clarify the role of PPARalpha in vascular disease, we crossed PPARalpha-null mice with apoE-null mice to determine if the genetic absence of PPARalpha affects vascular disease in a robust atherosclerosis model. On a high-fat diet, concentrations of atherogenic lipoproteins were higher in PPARalpha(-/-)apoE(-/-) than in PPARalpha(+/+)apoE(-/-) mice, due to increased VLDL production. However, en face atherosclerotic lesion areas at the aortic arch, thoracic aorta, and abdominal aorta were less in PPARalpha-null animals of both sexes after 6 and 10 weeks of high-fat feeding. Despite gaining as much or more weight than their PPARalpha(+/+)apoE(-/-) littermates, PPARalpha(-/-)apoE(-/-) mice had lower fasting levels of glucose and insulin. PPARalpha-null animals had greater suppression of endogenous glucose production in hyperinsulinemic clamp experiments, reflecting less insulin resistance in the absence of PPARalpha. PPARalpha(-/-)apoE(-/-) mice also had lower blood pressures than their PPARalpha(+/+)apoE(-/-) littermates after high-fat feeding. These results suggest that PPARalpha may participate in the pathogenesis of diet-induced insulin resistance and atherosclerosis.
Subject(s)
Apolipoproteins E/physiology , Arteriosclerosis/pathology , Insulin Resistance , Receptors, Cytoplasmic and Nuclear/physiology , Transcription Factors/physiology , Animals , Aorta/metabolism , Apolipoproteins E/genetics , Apolipoproteins E/metabolism , Arteriosclerosis/metabolism , Blood Pressure , CD36 Antigens/genetics , Chemokine CCL2/genetics , Dietary Fats/metabolism , Female , Gene Expression , Glucose/metabolism , Lipoprotein Lipase/metabolism , Lipoproteins/metabolism , Macrophages/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Pyrimidines/metabolism , Receptors, Cytoplasmic and Nuclear/genetics , Receptors, Cytoplasmic and Nuclear/metabolism , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
Few population studies have measured urinary levels of pesticides in individuals with vegan, vegetarian, or organic diets. The objectives of this study were to evaluate whether a vegan/vegetarian diet was associated with increased exposure to organophosphate and carbamate pesticides, and to evaluate the impact of organic consumption on pesticide exposure in vegans and vegetarians. In the current pilot study conducted in 2013-2014, we collected spot urine samples and detailed 24h recall dietary data in 42 adult residents of Amirim, a vegetarian community in Northern Israel. We measured urinary levels of non-specific organophosphate pesticide metabolites (dialkylphosphates, (DAPs)) and specific metabolites of the current-use pesticides chlorpyrifos (3,5,6-trichloro-2-pyridinol (TCPy)), propoxur (-isopropoxyphenol (IPPX)), and carbaryl (1-naphthol). Six DAP metabolites were detected in between 67 and 100% of urine samples, with highest geometric mean concentrations for dimethylphosphate (19.2µg/g). Creatinine-adjusted median concentrations of total DAPs and of TCPy were significantly higher in Amirim residents compared to the general Jewish population in Israel (0.29µmol/g compared to 0.16, p<0.05 for DAPs and 4.32µg/g compared to 2.34µg/g, p<0.05 for TCPy). Within Amirim residents, we observed a positive association between vegetable intake and urinary TCPy levels (rho=0.47, p<0.05) and lower median total dimethyl phosphate levels in individuals reporting that >25% of the produce they consume is organic (0.065µmol/L compared to 0.22, p<0.05). Results from this pilot study indicate relatively high levels of urinary organophosphate pesticide metabolite concentrations in residents of a vegetarian community, a positive association between vegetable intake and urinary levels of a chlorpyrifos specific metabolite, and lower levels of total dimethyl phosphate in individuals reporting higher intake of organic produce. Results suggest that consumption of organic produce may offer some protection from increased exposure to organophosphate pesticide residues in vegetarians.
Subject(s)
Carbamates/urine , Organophosphates/urine , Pesticides/urine , Vegetarians/statistics & numerical data , Adult , Chlorpyrifos/urine , Diet , Diet, Vegetarian , Environmental Exposure/analysis , Female , Food, Organic , Humans , Insecticides/urine , Israel , Male , Middle Aged , Naphthols/urine , Organophosphorus Compounds/urine , Pesticide Residues , Pilot ProjectsABSTRACT
A 71-year-old hypertensive patient experienced a severe hypertensive crisis. His blood pressure was 300/200 mm Hg three days after nifedipine therapy was discontinued. He had been taking nifedipine together with methyldopa. During five months on the combined treatment, his blood pressure had not risen higher than 170/100 mm Hg. A severe hypertensive crisis following abrupt nifedipine withdrawal has not been previously reported, to our knowledge. We recommend that caution be used when abrupt cessation of nifedipine therapy is considered in the treatment of hypertension.
Subject(s)
Hypertension/etiology , Nifedipine/administration & dosage , Aged , Humans , MaleABSTRACT
The role of the low dose (1 microgram) ACTH stimulation test in the evaluation of patients with pituitary diseases was systematically assessed by relating its results to those obtained on gold standard tests of hypothalamo-pituitary-adrenal (HPA) reserve, such as insulin-induced hypoglycemia or a metyrapone challenge. Ten patients with pituitary diseases (8 men and 2 women) and proven impairment of HPA function and 9 patients (5 men and 4 women) with similar pituitary pathologies but preserved HPA function were studied (pituitary controls). A group of 7 normal volunteers (3 men and 4 women) served as normal controls. None of the subjects was taking glucocorticoids on a chronic basis or had been taking any recently. All subjects underwent ACTH tests at 0800 h with 3 different levels of stimulation (1, 5, and 250 micrograms), and serum cortisol was assayed 0, 30, and 60 min after injection. A pass result was defined as a peak cortisol value of 497 nmol/L or more. Basal cortisol values were indistinguishable among the groups. Pituitary controls did not differ from normal controls for any of the challenges. In healthy controls, peak cortisol levels attained with the low dose stimulation were clearly lower than with the standard dose (670 +/- 39 vs. 919 +/- 50 nmol/L; P = 0.002). However, every normal control passed the low dose stimulation, whereas none of the patients with impaired HPA function did (P = 0.00005). Although the cortisol values achieved on the standard (250 micrograms) dose by the subjects with impaired HPA function were significantly lower than those in normal controls (P < 0.005), they were generally normal in absolute terms. Indeed, using the peak value criterion, 7 of these 10 patients would have qualified as pass on the 5-micrograms challenge, and 9 of 10 would have passed the 250-micrograms test. Thus, the low dose ACTH test appears to perform better than the standard pharmacological test. As we have shown that this test correlates well with reference tests of HPA function, it is suggested that it should replace the standard ACTH test in the diagnosis of secondary adrenal insufficiency.
Subject(s)
Adrenocorticotropic Hormone , Pituitary Diseases/diagnosis , Adrenocorticotropic Hormone/administration & dosage , Adult , Aged , Aged, 80 and over , Dose-Response Relationship, Drug , Female , Humans , Hypoglycemia/chemically induced , Hypothalamo-Hypophyseal System/physiopathology , Insulin , Male , Metyrapone , Middle Aged , Pituitary-Adrenal System/physiopathologyABSTRACT
The majority of pituitary tumors are of monoclonal origin; however, the molecular basis for their formation is poorly understood. Somatic mutations in the alpha-subunit of the GTP-binding protein, Gs alpha (gsp oncogene) have been found in about one third of GH-secreting tumors. Mutations in another alpha-subunit of a GTP-binding protein, Gi2 alpha (gip mutations) have been described in other endocrine tumors. In this study, we examined 21 nonfunctioning pituitary tumors and 4 macroprolactinomas for gsp mutations and 27 nonfunctioning tumors and 4 macroprolactinomas for gip mutations. Using the polymerase chain reaction and denaturing gradient gel electrophoresis, 2 nonfunctioning pituitary tumors displayed migration abnormalities when the Gs alpha-gene was analyzed. Sequence analysis of these abnormally migrating polymerase chain reaction products revealed two previously known gsp mutations: arginine at codon 201 altered to cysteine, and glutamine at codon 227 changed to leucine. No gip mutations could be demonstrated. These findings emphasize the monoclonal origin of nonfunctioning pituitary tumors and suggest that cAMP may play a role in tumorigenesis of nonfunctioning pituitary tumors.
Subject(s)
GTP-Binding Proteins/genetics , Mutation , Pituitary Neoplasms/genetics , Prolactinoma/genetics , Adrenocorticotropic Hormone/analysis , Adult , Aged , Base Sequence , Codon , Electrophoresis, Polyacrylamide Gel , Exons , Female , Follicle Stimulating Hormone/analysis , Growth Hormone/analysis , Humans , Immunoenzyme Techniques , Luteinizing Hormone/analysis , Male , Middle Aged , Molecular Sequence Data , Polymerase Chain Reaction , Prolactin/analysis , Sequence Analysis, DNAABSTRACT
Pre- and postoperative anterior pituitary function was assessed in 26 subjects with nonfunctioning macroadenoma (NFMA) and in 15 acromegalic subjects with macroadenomas. Preoperatively, NFMA patients had a higher prevalence of secondary hypogonadism (78% vs. 40%; P < 0.05), hypothyroidism (23% vs. 0%; P = 0.06), and hypoadrenalism (43% vs. 7%; P = 0.02) compared to individuals with GH-secreting macroadenoma (GHMA). Patients with NFMA also had a higher prevalence of more severe pituitary failure compared with acromegalic patients; 56% of the patients in this group had more than one pituitary hormone axis impaired compared to only 8% in the acromegalic group. These differences could not be accounted for by tumor grade and/or stage. Transsphenoidal pituitary surgery led to a significant improvement in anterior pituitary function in the NFMA group. Nevertheless, the prevalence of pituitary deficiency postoperatively was still significantly greater in NFMA patients than in the acromegalic group (68% vs. 17%, respectively; P < 0.04). The results suggest that anterior pituitary function is better preserved in GHMA than in NFMA and that this difference is independent of tumor size. The mechanism underlying the lower rate of hypopituitarism in acromegalics with macroadenomas remains to be elucidated.
Subject(s)
Adenoma/metabolism , Adenoma/physiopathology , Growth Hormone/metabolism , Pituitary Gland, Anterior/physiopathology , Pituitary Neoplasms/metabolism , Pituitary Neoplasms/physiopathology , Acromegaly/physiopathology , Acromegaly/surgery , Adenoma/surgery , Adult , Female , Humans , Male , Middle Aged , Pituitary Neoplasms/surgery , Postoperative PeriodABSTRACT
Recently several members of the glucose transporter family have been identified by molecular cloning techniques. We determined the effect of a 4-h insulin infusion on the expression of the muscle/adipose tissue (GLUT-4) glucose transporter mRNA and protein in 14 insulin-treated type 1 diabetic patients and 15 matched nondiabetic subjects. GLUT-4 mRNA and protein concentrations were determined in muscle biopsies taken before and at the end of the insulin infusion during maintenance of normoglycemia. In response to insulin, muscle GLUT-4 mRNA increased in the nondiabetic subjects from 24 +/- 3 to 36 +/- 4 pg/microgram RNA (P less than 0.001) but remained unchanged in the insulin-resistant diabetic patients (24 +/- 2 vs. 26 +/- 2 pg/microgram RNA, before vs. after insulin). The glucose transporter protein concentrations were similar in the basal state and decreased by 21 +/- 7% (P less than 0.02) in the normal subjects but remained unchanged in the diabetic patients. The increase of the GLUT-4 mRNA and the decrease in the GLUT-4 protein correlated with the rate of glucose uptake [correlation coefficient (r) = -0.55, P less than 0.01, and r = -0.44, P less than 0.05, respectively]. We conclude that the insulin response of both the GLUT-4 glucose transporter mRNA and protein are absent in skeletal muscle of insulin-resistant type 1 diabetic patients. Thus, impaired insulin regulation of glucose transporter gene expression can be one of the underlying mechanisms of insulin resistance in type 1 diabetes.
Subject(s)
Adipose Tissue/metabolism , Diabetes Mellitus, Type 1/genetics , Gene Expression , Insulin/pharmacology , Monosaccharide Transport Proteins/genetics , Muscle Proteins , Muscles/metabolism , Blood Glucose/metabolism , Diabetes Mellitus, Type 1/metabolism , Glucose Transporter Type 4 , Humans , Male , Monosaccharide Transport Proteins/metabolism , RNA, Messenger/metabolismABSTRACT
A case of long-standing idiopathic hypoparathyroidism that remained asymptomatic during pregnancy is described in a 25-year-old primipara. Clinical signs including carpopedal spasm, convulsions, and acute psychosis developed after the patient gave birth to a healthy infant. In contrast to previous reported cases, no signs of osteitis fibrosa cystica were found in the infant. This is believed to be the first such case described.
Subject(s)
Hypoparathyroidism/physiopathology , Postpartum Period , Adult , Female , Foot , Humans , Infant, Newborn , Pregnancy , Psychotic Disorders/physiopathology , Seizures/physiopathology , Spasm/physiopathology , WristABSTRACT
OBJECTIVE: To explore the hypothesis that most of the pituitary abnormalities compatible with the diagnosis of microadenoma, and detected in about 10% of the normal adult population, represent asymptomatic gonadotropinomas. DESIGN: Patients diagnosed with pituitary microincidentalomas at the Institute of Endocrinology of the Tel Aviv Medical Center were evaluated. Circulating beta-subunits of gonadotropin hormones were measured before and 30, 45, 60 and 90 min after the intravenous injection of 400 microgram TRH. PATIENTS: Twenty-two patients with pituitary incidentaloma and 16 normal volunteers were tested. RESULTS: In 16 of the 22 patients, an abnormal beta-subunit response was detected after the TRH challenge. Three patients had an abnormal increase in both beta-FSH and beta-LH after TRH administration. Isolated pathological beta-FSH or beta-LH responses were demonstrated in five and eight patients respectively. Six patients had normal basal and stimulated gonadotropin subunit values, raising the possibility that their lesions were not pituitary microadenomas. There was a significant overall difference between the response to TRH of the patient and control groups. In the gonadotropin positive group, comprising 16 patients, serum beta-FSH increased from 6.4+/-1.6 ng/ml to 9.2+/-1.3 ng/ml (P=0.042) 1 h after TRH stimulation, whereas no changes were detected in the control group after TRH injection (basal: 4.1+/-0.8 ng/ml, peak: 5.1+/-0.8 ng/ml; P=0.15). Serum beta-LH increased from 10.5+/-3.2 ng/ml to 23.4+/-4.9 ng/ml (P=0.0037) at this time, in contrast to a lack of response in controls (basal: 6.4+/-1.5 ng/ml, peak: 8.2+/-2.3 ng/ml; P=0.24). CONCLUSION: In about 73% of patients with pituitary incidentalomas smaller than 10 mm, TRH elicits an increase in gonadotropin beta-subunits. This observation raises the possibility that non-functioning pituitary micro- and macroadenomas, which share a similar response to TRH, originate in a common ancestor cell type, probably a pituitary gonadotrope.
Subject(s)
Adenoma/blood , Follicle Stimulating Hormone/blood , Luteinizing Hormone/blood , Pituitary Neoplasms/blood , Thyrotropin-Releasing Hormone , Adult , Female , Follicle Stimulating Hormone, beta Subunit , Humans , Kinetics , MaleABSTRACT
We have demonstrated previously that rat adipose tissue showed sex and depot-specific responses to gonadal steroids. The epididymal fat pad in males responded exclusively to androgens by increased specific activity of the brain type isozyme of creatine kinase (CK). In females, the parametrial adipose tissue responded exclusively to estrogens. The present study was undertaken to follow the responsiveness to steroid hormones, and the presence of estrogen receptors (ER), in 3T3L1 cells during their differentiation from pre-adipocytes to adipocytes. In pre-adipocytes in which the basal CK specific activity is low, there was no CK response to 17beta estradiol (E2) or dihydrotestosterone (DHT). Differentiation of the cells into adipocytes was accompanied by increased basal CK activity which was stimulated by E2, but not by DHT. Responsiveness to E2 began 5 days after switching pre-adipocytes to differentiation medium. Upon differentiation, ER became demonstrable in the cell nuclei by staining with FITC labeled anti-idiotypic antibody (clone 1D5) directed against the steroid binding domain of ER. The response to E2 was time-dependent and blocked completely by cycloheximide or actinomycin D. 1D5 itself, which has an estrogen mimetic effect, stimulated CK activity in the cells similarly to E2. The antiestrogen tamoxifen which also stimulated CK activity in the adipocytes, completely blocked E2 action. The 'pure' antagonist of E2, ICI 164,384 and the tissue-selective antiestrogens, raloxifene or tamoxifen methiodide were also complete antagonists with no agonistic effects. The response of the 3T3L1 adipocytes to E2 was upregulated by 1,25(OH)2D3. Moreover, IGF1 was also a potent stimulator of CK in these cells, and therefore may mediate partially the stimulation by E2. Transient transfection of the pre-adipocytes with ER permitted E2 induction of CK. Thus, the appearance of ER and concomitant responsiveness to E2 is another hormone-related change occurring in 3T3L1 cells during differentiation, in addition to changes such as development of insulin responsiveness. The interactions in this system provide a useful in vitro model for investigating the development of responsiveness to E2.
Subject(s)
Adipose Tissue/drug effects , Adipose Tissue/metabolism , Creatine Kinase/metabolism , Estradiol/pharmacology , Receptors, Estrogen/metabolism , 3T3 Cells , Adipose Tissue/cytology , Animals , Cell Differentiation/physiology , Cycloheximide/pharmacology , Dactinomycin/pharmacology , Dihydrotestosterone/pharmacology , Estrogen Antagonists/pharmacology , Female , Insulin-Like Growth Factor I/pharmacology , Isoenzymes , Kinetics , Male , Mice , Progesterone/pharmacology , Protein Synthesis Inhibitors/pharmacology , Rats , Receptors, Estrogen/genetics , Tamoxifen/pharmacology , TransfectionABSTRACT
Concern about cyclosporine causing adverse effects on glucose metabolism is based mainly on in vitro studies and in vivo data in rodents. However, data on large mammals and humans are much more controversial. Because the drug is used as therapy accompanying pancreatic or isolated islet transplantations, studies in large animals are needed to assess whether cyclosporine inhibits beta-cell function and causes glucose intolerance. To address these issues, we examined intravenous glucose tolerance, islet beta-cell function, and insulin sensitivity in a group of adult mongrel dogs with intrasplenic islet autografts, with and without cyclosporine treatment. Similar fasting plasma glucose and insulin values were found before and after pancreatectomy and islet transplantation. After intravenous glucose, plasma glucose values decreased more slowly in dogs that had undergone transplantation, but no additional adverse effect as a result of cyclosporine was observed. During euglycemic clamp studies, performed at both physiologic and pharmacologic insulin concentrations, the drug had no effect on the total amount of metabolized glucose, and glucose production was unaffected by cyclosporine treatment. Thus intramuscular cyclosporine therapy does not seem to inhibit insulin secretion from heterotopic islets or to affect peripheral and hepatic insulin sensitivity in dogs with intrasplenic islet autografts.
Subject(s)
Blood Glucose/metabolism , Cyclosporine/pharmacology , Insulin/metabolism , Islets of Langerhans Transplantation/physiology , Animals , Cyclosporine/blood , Dogs , Glucose Clamp Technique , Glucose Tolerance Test , Insulin/blood , Insulin/pharmacology , Insulin Secretion , Pancreatectomy , Spleen , Transplantation, Autologous , Transplantation, HeterotopicABSTRACT
BACKGROUND/OBJECTIVES: Often recommended, calcium supplements have been incriminated as increasing the risk of cardiovascular events, whereas dietary calcium has generally been exonerated. As a first step to address the vascular safety of such dietary measures at the clinical nutritionist toolbox, we sought to determine and compare the acute effects of a typical oral calcium load, provided either as a supplement or as food, on vascular parameters assessed noninvasively in healthy subjects. SUBJECTS/METHODS: In this acute, cross-over, random-order intervention, 11 young and healthy vitamin D-sufficient volunteers (8 women/3 men, 33±6.1 years, body mass index 22.6±2.3 kg/m(2)), ingested 600 mg of calcium twice, once as calcium citrate and the other time from dairy products. Biochemical, vascular and hemodynamic parameters, before and 2 h after each challenge, were compared. Arterial stiffness was studied by measuring pulse wave velocity, augmentation index and large (C1) and small (C2) arterial compliance. Endothelial function was assessed by flow-mediated dilation (FMD). RESULTS: Despite effective calcium loading accompanied by a significant 60% parathyroid hormone level reduction on both occasions, there were no clinically significant changes in the vascular parameters neither in comparison with baseline, nor between the studies. A decrease in heart rate with no change in cardiac output was noticed after the supplement. CONCLUSIONS: An effective calcium load has no clinically significant untoward effect on the vascular properties of young healthy subjects, regardless of its source. Additional studies should determine whether this holds true for chronic calcium supplementation, particularly in subjects with a priori vascular impairment.
Subject(s)
Arteries/drug effects , Calcium, Dietary/administration & dosage , Dietary Supplements , Endothelium/drug effects , Administration, Oral , Adult , Arteries/metabolism , Calcium, Dietary/adverse effects , Calcium, Dietary/blood , Calcium, Dietary/urine , Creatinine/blood , Creatinine/urine , Cross-Over Studies , Dose-Response Relationship, Drug , Endothelium/metabolism , Female , Healthy Volunteers , Heart Rate/drug effects , Humans , Male , Myocardial Infarction/blood , Myocardial Infarction/etiology , Parathyroid Hormone/blood , Phosphorus/blood , Random Allocation , Recommended Dietary Allowances , Vitamin D/administration & dosage , Young AdultABSTRACT
Chronic steroid treatment is known to impair the hypothalamic-pituitary adrenal axis (HPA) but the need to assess HPA function prior to withdrawal of steroid therapy in post-transplant patients has not been uniformly accepted. We evaluated the status of the HPA axis in 48 kidney or kidney-pancreas transplant patients who were considered for possible discontinuation of glucocorticoid therapy using a recently validated dynamic test of HPA integrity, the low-dose (1 microg) adrenocorticotropin (ACTH) test. HPA suppression was detected in 29 (60%) of the patients, four of which had severe hypoadrenalism prohibitive of steroid withdrawal. Neither the duration of steroid treatment nor 8:00 am serum cortisol was a useful marker of hypoadrenalism. 8:00 am cortisol in subjects with normal HPA reserve and subjects with partial hypoadrenalism overlapped considerably but levels <5 microg/dL were indicative of severe hypoadrenalism. Pre-withdrawal diagnosis of partial hypoadrenalism allowed the identification of subjects requiring no further steroid replacement under regular daily circumstances. However glucocorticoid supplementation was prescribed in the event of stress such as infection, exceptional effort, trauma or surgery. Individuals with partial HPA impairment, but not patients with severe HPA suppression, improved upon retesting 3 months later. Patients exhibiting normal response to 1 mcg ACTH enjoyed an uneventful course following steroid withdrawal. Since hypoadrenalism is extremely common in post-transplant patients, we recommend the use of the low-dose ACTH test as a convenient method to identify patients with various degrees of hypoadrenalism prior to steroid withdrawal.