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V Daniel Castracane

Publications and source records attributed to V Daniel Castracane.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of hormone responses following light resistance exercise with partial vascular occlusion and moderately difficult resistance exercise without occlusion.

Previous studies of contracting muscle with low loading and partial vascular occlusion demonstrated hypertrophy and strength adaptations similar to and exceeding those observed with traditional moderate to high resistance (Shinohara M, Kouzaki M, Yoshihisa T, and Fukunaga T. Eur J Physiol 77: 189-191, 1998; Takarada Y, Takazawa H, Sato Y, Takebayashi S, Tanaka Y, and Ishii N. J Appl Physiol 88: 2097-2106, 2000; Takarada Y, Sato Y, and Ishii N. Eur J Physiol 86: 308-314, 2002). The purpose of the study was to determine the anabolic and catabolic hormone responses to light resistance exercise combined with partial vascular occlusion. Three experimental conditions of light resistance with partial occlusion (LRO), moderate resistance with no occlusion (MR), and partial occlusion without exercise (OO) were performed by eight healthy subjects [mean 21 yr (SD 1.8)]. Three sets of single-arm biceps curls and single-leg calf presses were completed to failure with 1-min interset rest periods. Workloads of 30 and 70% one repetition maximum for each exercise were lifted for the LRO and MR trials, respectively. Blood samples were taken preexercise, postexercise, and 15 min postexercise for each experimental condition. Lactate increased significantly in the LRO and MR trials and was not significantly different from each other at any time point. Growth hormone (GH) increased significantly by fourfold from pre- to postexercise in the LRO session but did not change significantly during this time period in the MR and OO trials (8.3 +/- 2.3 vs. 2.1 +/- 1.2 and 2.6 +/- 0.94 microg/l; respectively, P < 0.05). There were no changes in resting total testosterone [T; mean 15.7 +/- 1.6 (SE) nmol/l], free testosterone (FT; 54.1 +/- 4.5 pmol/l), or cortisol (267.6 +/- 22 nmol/l) across all trials and times. In conclusion, with similar lactate responses, light exercise combined with partial vascular occlusion elicits a greater GH response than moderate exercise without occlusion but does not affect T, FT, or cortisol.

Adolescent↗
PubMed2006

Detection of gestational diabetes mellitus by homeostatic indices of insulin sensitivity: a preliminary study.

OBJECTIVE: We investigated whether homeostatic indices of insulin sensitivity might suitably screen for gestational diabetes mellitus. STUDY DESIGN: One hundred twenty-three pregnant women who were between 24 and 28 weeks of gestation completed a 3-hour 100-g oral glucose challenge test and fasting insulin level in a nested case-control study design. Insulin sensitivity indices were calculated and tested for their ability to detect gestational diabetes mellitus. RESULTS: Fasting glucose demonstrated the best overall accuracy, but the homeostasis model assessment and quick insulin sensitivity check index were also sensitive screening techniques for gestational diabetes mellitus when either the National Diabetes Data Group or Carpenter-Coustan criteria were used. CONCLUSION: Homeostasis model assessment, quick insulin sensitivity check index, and fasting glucose are sensitive screening tests for gestational diabetes mellitus and can avoid oral administration of glucose-containing solutions.

Adult↗
PubMed2006

Interrelationships of serum estradiol, estrone, and estrone sulfate, adiposity, biochemical bone markers, and leptin in post-menopausal women.

OBJECTIVE: The aim of this study was to examine the relationships between endogenous estrogens and adiposity, bone markers, and leptin in post-menopausal (PM) women. DESIGN: Seventy-three post-menopausal (PM) women participated in a clinical correlational study. Weight, height, waist-hip ratio, fasted morning serum and first morning voided urine samples were obtained to compare body mass index (BMI), waist-hip ratio, endogenous estrogens, leptin, and bone markers. Serum estradiol, estrone (E1), estrone sulfate (E1S), leptin, osteocalcin, and urinary deoxypyridinoline (Dpd) were determined. RESULTS: Significant positive relationships were found between BMI and estradiol, E1, and E1S (r = 0.52, 0.38, and 0.29; P < or = 0.001, 0.001, and 0.013 respectively). Significant relationships between leptin and estrogens were revealed, but were not significant when BMI was used as a covariate. Although many subjects revealed elevated bone marker levels, no correlation between estrogens or BMI and bone markers (Dpd and osteocalcin) was found. CONCLUSIONS: There are significant positive correlations between estrogens and BMI in PM women. Increasing levels of estradiol, E1, and E1S with increasing BMI may be an indicator of adiposity, but are without effect as a stimulatory factor on leptin production. Waist-hip ratio did not significantly affect leptin concentrations when accounting for BMI. Due to assay sensitivity in the present study, data represent a more precise representation of these relationships. The lack of correlation between estrogens and bone marker levels may have been due to low estrogen levels in PM women.

Adipose Tissue↗
PubMed2006

Hyperinsulinemia and circulating dehydroepiandrosterone sulfate in white and Mexican American women with polycystic ovary syndrome.

OBJECTIVE: To determine whether Mexican American women with polycystic ovary syndrome (PCOS), a population more insulin resistant than white women with PCOS, demonstrate differences in adrenal androgen production. DESIGN: Retrospective study. SETTING: University gynecology clinic and research laboratory. PATIENT(S): One hundred eleven white women and 50 Mexican American women with PCOS based on the 2003 Rotterdam Consensus Statement. INTERVENTION(S): Blood sampling, oral glucose tolerance testing, and ultrasonography. MAIN OUTCOME MEASURE(S): Serum total T, free T, DHEAS, and calculation of multiple insulin sensitivity indices after an oral glucose challenge. RESULT(S): Mexican American women with PCOS were significantly more insulin resistant than their white counterparts but had lower circulating levels of DHEAS, a reliable index of adrenal androgen production. Age and body mass index (BMI) were each inversely proportional to serum DHEAS, but no association was found between circulating insulin and serum DHEAS levels. Testosterone levels were similar between groups. CONCLUSION(S): The lower levels of DHEAS observed in the more insulin resistant Mexican American group with PCOS (compared to a similar group of white women living in the same locale) further corroborates the extent of phenotypic variability among specific PCOS populations. Hyperinsulinemia does not appear to significantly influence circulating adrenal androgen levels in PCOS.

Adult↗
PubMed2005

Similar hormonal responses to concentric and eccentric muscle actions using relative loading.

Conventional resistance exercise is performed using sequential concentric (CON) and eccentric (ECC) contractions, utilizing the same muscle load. Thus, relative to maximal CON and ECC resistance, the ECC contraction is loaded to a lesser degree. We have recently shown that at the same absolute load, CON contractions are associated with greater growth hormone (GH) but similar total testosterone (TT) and free testosterone (FT) responses compared with ECC contractions and attributed the larger GH response to greater relative CON loading. In the present study, we have examined the same endocrine parameters to six different upper and lower body exercises using relative loading rather than absolute loading, hypothesizing that GH responses would be similar for CON and ECC actions, but TT and FT responses would be greater after ECC contractions. Seven young men with recreational weight training experience completed an ECC and CON muscle contraction trial on two different occasions in a counterbalanced fashion. The exercises consisted of four sets of 10 repetitions of lat pull-down, leg press, bench press, leg extension, military press, and leg curl exercises at 65% of an ECC or CON 1-RM with 90 s between sets and exercises. CON and ECC actions were performed at the same speed. ECC 1-RMs were considered to be 120% of the CON 1-RM for the same exercise. Blood samples were collected before, immediately after, and 15 min after the exercise. GH significantly increased across both trials but was not different between the two trials. Total testosterone was not significantly altered in response to either trial; however, free testosterone concentrations increased in response to both ECC and CON trials. Data suggest that CON and ECC muscle contractions produce similar GH, T, and free testosterone responses with the same relative loading.

Adaptation, Physiological↗
PubMed2005

Leptin in pregnancy: an update.

Leptin influences satiety, adiposity, and metabolism and is associated with mechanisms regulating puberty onset, fertility, and pregnancy in various species. Maternal hyperleptinemia is a hallmark of mammalian pregnancy, although both the roles of leptin and the mechanisms regulating its synthesis appear to be taxa specific. In pregnant humans and nonhuman primates, leptin is produced by both maternal and fetal adipose tissues, as well as by the placental trophoblast. Specific receptors in the uterine endometrium, trophoblast, and fetus facilitate direct effects of the polypeptide on implantation, placental endocrine function, and conceptus development. A soluble isoform of the receptor may be responsible for inducing maternal leptin resistance during pregnancy and/or may facilitate the transplacental passage of leptin for the purpose of directly regulating fetal development. The steroid hormones are linked to the regulation of leptin and the leptin receptor and probably interact with other pregnancy-specific, serum-borne factors to regulate leptin dynamics during pregnancy. In addition to its effects on normal conceptus development, leptin is linked to mechanisms affecting a diverse array of pregnancy-specific pathologies that include preeclampsia, gestational diabetes, and intrauterine growth restriction. Association with these anomalies and with mechanisms pointing to a fetal origin for a range of conditions affecting the individual's health in adult life, such as obesity, diabetes mellitus, and cardiovascular disease, reiterate the need for continued research dedicated to elucidating leptin's roles and regulation throughout gestation.

Animals↗
PubMed2005

Impact of the selective serotonin reuptake inhibitor citalopram on insulin sensitivity, leptin and basal cortisol secretion in depressed and non-depressed euglycemic women of reproductive age.

INTRODUCTION: Major depression in women of reproductive age may be accompanied by multiple endocrine and metabolic disturbances, which, in turn, may affect reproductive functioning. Enhanced cortisol synthesis, impaired leptin production and diminished insulin sensitivity have been reported in some depressed populations. We sought to determine whether an 8-week administration of citalopram would have an effect on these endocrine factors in a group of euglycemic depressed and non-depressed women of reproductive age. MATERIALS AND METHODS: Fourteen depressed and 18 non-depressed women (diagnosed by structured clinical interview) aged between 18 and 45 years completed an 8-week study. All depressed women were treated with citalopram and non-depressed subjects randomized to citalopram or no treatment in an open label cohort study. An oral glucose tolerance test with insulin levels was performed at baseline and at the end of the 8-week trial. Weight, blood pressure, fasting serum cortisol, fasting serum leptin and Beck Depression Inventory were assessed at baseline, 2, 4 and 8 weeks. RESULTS: Citalopram significantly improved depressive symptoms and Beck Depression Inventory scores in the depressed cohort. Cortisol production was higher in depressed women but did not diminish with citalopram therapy over 8 weeks. Indices of insulin sensitivity and leptin production were similar between depressed and non-depressed women and did not change despite citalopram therapy. CONCLUSION: . Insulin sensitivity in moderately depressed women of reproductive age does not differ from that in a similar group of non-depressed women. Insulin sensitivity, cortisol secretion and leptin production do not change significantly in depressed women following an 8-week course of citalopram despite substantial improvement in depression scores.

Administration, Oral↗
PubMed2005

Serum leptin in nonpregnant and pregnant women and in old and new world nonhuman primates.

Leptin is a hormone that is produced during mammalian pregnancy in the placental trophoblast and other tissues, including! fetal and maternal adipocytes. Synthesis of the polypeptide and the presence of its specific receptors throughout the human maternal fetoplacental unit suggest direct effects on conceptus growth and development. However, both the physiologic roles of leptin and the mechanisms regulating leptin synthesis in human pregnancy differ from those in laboratory and domestic species, necessitating the development of non-human primate research models. Therefore, we compared serum leptin concentrations in nonpregnant and pregnant women with those in both old world nonhuman primates (i.e., baboon, rhesus monkey, cynomolgus monkey) and new world nonhuman primates (i.e., squirrel monkey, titi monkey). As expected, maternal leptin levels were elevated in human and baboon pregnancies (P < 0.05 and P < 0.001, respectively). Levels in both species of old world monkeys were also greatly enhanced (P < 0.001). Although maternal serum concentrations were slightly elevated compared to nonpregnant levels in both species of new world monkeys, overall concentrations were dramatically lower than for either old world primates or humans. Results provide comparisons of serum leptin concentrations in pregnant and nonpregnant humans and baboons with those in both old and new world monkeys and further characterize these nonhuman primates as models for the investigation of leptin dynamics in pregnancy.

Animals↗
PubMed2004

Two isoforms of the leptin receptor are enhanced in pregnancy-specific tissues and soluble leptin receptor is enhanced in maternal serum with advancing gestation in the baboon.

Leptin is a polypeptide hormone produced by adipose and other endocrine tissues. Although it has been linked to receptor-mediated pathways that directly influence human conceptus development, mechanisms that regulate the leptin receptor in pregnancy-specific tissues remain unclear. Therefore, we assessed leptin-receptor ontogeny and regulation in the baboon (Papio sp.), a primate model for human pregnancy. Placentae, decidua, and amniochorion were collected from baboons in early (Days 54-63, n = 4), mid (Days 98-103, n = 4), and late (Days 159-165, n = 4) gestation. Regulation by estrogen was assessed by elimination of androgen precursors via removal of the fetus (fetectomy) at midgestation and collection of tissues in late gestation (n = 4; term, approximately 184 days). Maternal serum was sampled with advancing gestation, and the abundance of soluble leptin receptor (solLepR), a potential mediator of gestational hyperleptinemia, was determined. Two placental leptin-receptor isoforms (130 and 150 kDa) increased (P < 0.04 and P < 0.02, respectively) in abundance with advancing gestation. Similarly, the 130-kDa isoform increased approximately fourfold (P < 0.0025) in decidua and approximately 10-fold (P < 0.015) in amniochorion between early and late gestation. Following fetectomy, maternal serum estradiol levels declined approximately 85% (P < 0.03), and the 150-kDa placental leptin-receptor isoform was reduced by more than half (P < 0.002). Maternal serum solLepR concentrations were correlated with gestational age (r = 0.52, P < 0.01) and were unaffected by fetectomy. The presence of leptin-receptor isoforms in pregnancy-specific tissues further denoted leptin's potential to directly influence conceptus development, whereas the 130-kDa solLepR identified in maternal serum suggested a means to facilitate the hyperleptinemia typical of primate pregnancy. Although estrogen did not appear to be the principal regulator of solLepR, it and other factors linked to advancing gestation may be implicated in the regulation of leptin-receptor synthesis.

Animals↗
PubMed2004

Energy homeostasis, obesity and eating disorders: recent advances in endocrinology.

Health problems resulting from obesity could offset many of the recent health gains achieved by modern medicine, and obesity may replace tobacco as the number one health risk for developed societies. An estimated 300,000 deaths per year and significant morbidity are directly attributable to obesity, mainly due to heart disease, diabetes, cancer, asthma, sleep apnea, arthritis, reproductive complications and psychological disturbances. In parallel with the increasing prevalence of obesity, there has been a dramatic increase in the number of scientific and clinical studies on the control of energy homeostasis and the pathogenesis of obesity to further our understanding of energy balance. It is now recognized that there are many central and peripheral factors involved in energy homeostasis, and it is expected that the understanding of these mechanisms should lead to effective treatments for the control of obesity. This brief review discusses the potential role of several recently discovered molecular pathways involved in the control of energy homeostasis, obesity and eating disorders.

Adiponectin↗
PubMed2004

Detecting insulin resistance in polycystic ovary syndrome: purposes and pitfalls.

Approximately 50% to 70% of all women with polycystic ovary syndrome (PCOS) have some degree of insulin resistance, and this hormone insensitivity probably contributes to the hyperandrogenism that is responsible for the signs and symptoms of PCOS. Although uncertainty exists, early detection and treatment of insulin resistance in this population could ultimately reduce the incidence or severity of diabetes mellitus, dyslipidemia, hypertension, and cardiovascular disease. Even if that proves to be the case, there are still several problems with our current approach to insulin sensitivity assessment in PCOS, including the apparent lack of consensus on what defines PCOS and "normal" insulin sensitivity, ethnic and genetic variability, the presence of other factors contributing to insulin resistance such as obesity, stress, and aging, and concern about whether simplified models of insulin sensitivity have the precision to predict treatment needs, responses, and future morbidity. Although the hyperinsulinemic-euglycemic clamp technique is the gold standard for measuring insulin sensitivity, it is too expensive, time-consuming, and labor-intensive to be of practical use in an office setting. Homeostatic measurements (fasting glucose/insulin ratio or homeostatic model assessment [HOMA] value) and minimal model tests (particularly the oral glucose tolerance test [OGTT]) represent the easiest office-based assessments of insulin resistance in the PCOS patient. The OGTT is probably the best simple, office-based method to assess women with PCOS because it provides information about both insulin resistance and glucose intolerance. The diagnosis of glucose intolerance holds greater prognostic and treatment implications. All obese women with PCOS should be screened for the presence of insulin resistance by looking for other stigmata of the insulin resistance syndrome such as hypertension, dyslipidemia, central obesity, and glucose intolerance.

Diabetes Mellitus↗
PubMed2003

Variability of serum estrogens among postmenopausal women treated with the same transdermal estrogen therapy and the effect on androgens and sex hormone binding globulin.

OBJECTIVE: To examine the variability of serum estrogens in response to transdermal estrogen replacement therapy (ET), and to determine the effects on androgens and sex hormone binding globulin (SHBG). DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Women's hospital. PATIENT(S): Two groups of postmenopausal women: [1] 21 women not on ET enrolled and 17 completed the study; [2] 19 women on continuous transdermal ET enrolled and 13 completed the study. INTERVENTION(S): Women not on ET were administered a placebo patch or a newly initiated estrogen patch, then crossed over to the alternate treatment. Serum samples were obtained at baseline and the subsequent 3 days from the placebo and new-patch groups and from a separate group of women receiving continuous estrogen patch treatment. MAIN OUTCOME MEASURE(S): Estradiol (E(2)), estrone, estrone sulfate, T, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), androstenedione, free androgen index, and SHBG. RESULT(S): There was considerable intrapatient and interpatient variability in the estrogen response to identical treatment doses, with E(2) values differing between women as much as 138 pg/mL and E(2) increases above baseline differing as much as 90 pg/mL. Continuous treatment increased SHBG and decreased androstenedione levels; however, levels of T, DHEA, DHEAS, and free androgen index did not change. CONCLUSION(S): There is great variability of estrogen in response to transdermal ET, but minimal effect on circulating androgens.

Administration, Cutaneous↗
PubMed2003

Premature ovarian failure associated with autoimmune polyglandular syndrome: pathophysiological mechanisms and future fertility.

BACKGROUND: Autoimmune polyglandular syndromes (APS) are a series of disorders characterized by autoimmunity against two or more endocrine organs. Premature ovarian failure (POF) may also have an autoimmune origin and, when accompanied by other autoimmune endocrinopathies, may be part of the APSs. Onset of autoimmune ovarian failure usually occurs in childhood, adolescence, or adulthood, and as a result, fertility may be severely compromised. CASE REPORT: A 26-year-old women with secondary amenorrhea, Addison's disease, and autoimmune hypothyroidism requested infertility evaluation. Examination, transvaginal ultrasonography, endocrine evaluation, and ovarian biopsy were performed. 21-Hydroxylase and antithyroid antibodies were demonstrated, but ovarian steroid cell antibodies (StCA) were absent at the time of her infertility evaluation. Transvaginal sonography demonstrated only a few ovarian follicles. An ovarian biopsy revealed lymphocytic infiltration of the ovary. This presentation is consistent with APS type II accompanied by autoimmune POF. DISCUSSION: Unlike APS types I and III, autoimmune POF is more commonly encountered with APS types I and III than with APS type II. An autoimmune response to steroidogenic enzymes and ovarian steroid cells appears to mediate destruction of ovarian function. Although immunotherapy with corticosteroids (with or without in vitro fertilization [IVF]) may be successful in limited cases where several follicles are present, oocyte donation with IVF may be the best option for the patient seeking fertility, particularly in the absence of ovarian follicles. CONCLUSIONS: Advances in molecular genetics may be valuable in predicting and counseling women at risk for APS and POF, and cryopreservation of ovarian tissue may offer hope to affected unmarried young women. It is reasonable to suggest that children and reproductive aged women with one autoimmune disorder should be periodically screened for other autoimmune disorders.

Adult↗
PubMed2003

Changes in circulating leptin, leptin receptor, and gonadal hormones from infancy until advanced age in humans.

We determined developmental changes in circulating levels of the soluble leptin receptor (sOB-R), leptin, and gonadal hormones in human subjects. In both sexes the rise in leptin with age was associated with a decline in sOB-R, and age-related changes in both parameters preceded the pubertal rise in gonadal hormones. Leptin levels above 10 ng/ml were a strong predictor of sOB-R concentrations, but this predictive value decreased as leptin declined. In young subjects there were no gender differences in serum leptin, but boys had higher sOB-R levels. In adults neither leptin nor sOB-R changed with age, but serum leptin was higher and sOB-R was lower in women than men. There was a significant negative correlation between sOB-R and leptin in women, but not men. The data suggest that bioavailable leptin in the circulation may be increasing more rapidly during development than indicated by total leptin levels, and that these changes may serve as one of the signals to the central nervous system that metabolic conditions are adequate to support pubertal development. Furthermore, the study provides suggestive evidence that leptin regulates the secretion of its own binding protein, but it also appears that an additional gender-specific, leptin-independent, regulatory mechanism is functional before puberty.

Adolescent↗
PubMed2003

Hormonal responses from concentric and eccentric muscle contractions.

UNLABELLED: Intense resistance exercise can acutely increase testosterone (T), free testosterone (FT), and growth hormone (GH) concentrations, but there are few investigations concerning acute endocrine responses to concentric (CON) and eccentric (ECC) contractile actions. PURPOSE: The purpose of the study was to compare acute anabolic hormonal responses to bouts of dynamic CON and ECC contractions from multiple exercises at the same absolute load. METHODS: Ten young men (age: 24.7 +/- 1.2 yr, weight: 85.45 +/- 24.2 kg, and height: 178 +/- 0.2 cm) completed two trials in counterbalanced fashion consisting of only CON or ECC contractions at the same absolute workload. Subjects performed four sets of 12 repetitions of bench press, leg extension, military press, and leg curl at 80% of a 10-repetition maximum with 90-s rest periods. Blood samples were collected pre-, post-, and 15-min postexercise. RESULTS: There were significant increases in GH, T, and FT and lactate for both trials, but only GH and lactate were greater for the CON trial. CONCLUSION: CON exercise increases GH concentrations to a much greater extent than ECC exercise at the same absolute load, and it is likely that greater GH responses were related to intensity rather than mode of contraction. Also, CON and ECC dynamic contraction trials at the same absolute workload elicited similar small but significant increases in T and FT, indicating that the greater metabolic stress produced by during the CON trial did not affect these hormone responses.

Adult↗
PubMed2003

RPE, pain, and physiological adjustment to concentric and eccentric contractions.

PURPOSE: The purpose of the study was to compare perceptual (RPE and pain), cardiac (heart rate), lactate, and endocrine (cortisol) responses with concentric (CON) and eccentric (ECC) resistance exercise protocols using the same absolute workload. METHODS: Eight healthy men with resistance-training experience participated in the study. Subjects completed two experimental trials consisting of either CON contractions or ECC contractions at the same absolute workload for each of four exercises: bench press, leg extension, military press, and leg curl. Subjects performed four sets of 12 repetitions at 80% of 10-RM with 90-s rest periods. Blood samples were taken before, immediately after, and 15-min postexercise. RESULTS: There was a significant trial effect for RPE, with CON exercise eliciting a higher RPE than ECC exercise (6.71 +/- 0.51 and 4.10 +/- 0.27, respectively). A significant trial effect was also demonstrated for pain, with CON exercise producing a higher pain rating than ECC exercise (5.59 +/- 0.41 and 3.23 +/- 0.27, respectively). Significantly higher heart rates and lactates were also demonstrated during the CON trial. For cortisol, a significant interaction was revealed between the pre- and immediate posttrial measures but not an overall trial effect. Correlational analyses revealed a significant relationship between RPE and pain for both trials. CONCLUSIONS: CON exercise elicits greater perceptual (higher RPE and pain rating), cardiac, lactate and cortisol response than ECC exercise at the same absolute workload. Data demonstrate that relative to absolute load, RPE and pain respond to resistance exercise in a similar fashion. Additionally, physiological cues are consistent with these perceptual data.

Adolescent↗