Increased Hormone Concentrations Research Articles

The Impact of Folic Acid and B12 Administration on Growth, Wool Traits and Some Hormones Concentrations of Male Arabi Lambs

This study aimed to investigate the effects of folic acid and vitamin B12 administration on the growth and wool traits in male lambs. A total of fifteen animals was used from 1st February 2015 to 30th April 2015, divided into three treatment groups. The first group served as a control, the second group received a folic acid dosage equivalent to 0.5 mg per kilogram of body weight per head, and the third group received a vitamin B12 dosage equivalent to 0.1 mg per kilogram of body weight per head. The vitamins were administered orally twice a week. The results showed a significant improvement (P<0.05) in final body weight, daily gain, and total weight gain in the vitamin B12 and folic acid groups compared to the control group. Additionally, there was a significant (P<0.05) increase in all wool characteristics, except for crimp number, in the folic acid group compared to the control group. The study demonstrated significant relationships between body weight and every aspect of wool quality except for fiber length. There was a significant (P<0.05) increase in the concentrations of growth and thyroxine hormones in the vitamin B12 and folic acid groups compared to the control group, particularly in the second and third months of the experiment. No significant difference in insulin hormone concentration among the groups was observed during the 90-day experiment. In conclusion, administering vitamin B12 and folic acid are orally administered twice a week to improve growth, increase hormone concentrations (thyroxine and growth hormone), and improve wool quality

Dietary encapsulated Bacillus subtilis and essential oil supplementation improves reproductive performance and hormone concentrations of broiler breeders during the late laying period

This study was conducted to evaluate the effects of increasing inclusion rates of Bacillus subtilis and essential oil (BSEO) on egg production, hatching traits, egg quality, plasma antioxidant capacity, immune response, and hormone concentrations of broiler breeders during the late laying period. A total of 576 broiler breeders at 54 wk of age were randomly allocated to 4 treatments with 6 replicates of 24 broiler breeders per replicate. The experiment lasted for 12 wk and dietary treatments included corn-soybean meal-based diet supplemented with 0, 300, 600, and 900 mg/kg of BSEO. The BSEO supplementation decreased linearly (P < 0.05) the feed conversion ratio, the concentrations of tumor necrosis factor-gamma, and interleukin-6. As the dietary BSEO supplementation increased, the egg weight, fertility, hatchability, hatchability of fertile eggs, eggshell-breaking strength, eggshell thickness, yolk index, the activity of glutathione peroxidase, the concentrations of estradiol, parathyroid hormone, follicle-stimulating hormone, progesterone, and luteinizing hormone increased linearly (P < 0.05). In conclusion, BSEO contributed to better fertility, hatchability, and hatchability of fertile eggs and improved antioxidant capacity and immune response, and increased hormone concentrations in broiler breeders during the late laying period.

Essential oils disrupt steroidogenesis in a feto-placental co-culture model

We determined whether 5 common essential oils (basil, fennel seed, orange, black pepper and sage) interfered with feto-placental steroidogenesis in a co-culture model composed of fetal-like adrenocortical (H295R) and placental trophoblast-like (BeWo) cells. After a 24 h exposure, only basil and fennel seed oil significantly increased hormone concentrations of estradiol, estrone, dehydroepiandrosterone (DHEA), androstenedione, progesterone, and estriol. Basil and fennel seed oil were shown to significantly alter the expression of steroidogenic enzymes involved in cholesterol transport and steroid hormone biosynthesis, including StAR, CYP11A1, 3β-HSD1/2, SULT2A1, and HSD17β1, -4, and -5. Also, basil and fennel seed oil stimulated placental-specific promoter I.1 and pII-derived CYP19 mRNA in BeWo and H295R cells, respectively, as well as, increased CYP19 enzyme activity. Our results indicate that further study is necessary to determine the potential risks of using basil and fennel seed oils during pregnancy considering their potential to disrupt steroidogenic enzyme activity and expression in vitro.

Exogenous glucocorticoids amplify the costs of infection by reducing resistance and tolerance, but effects are mitigated by co-infection.

Individual variation in parasite defences, such as resistance and tolerance, can underlie heterogeneity in fitness and could influence disease transmission dynamics. Glucocorticoid hormone concentrations often change in response to fluctuating environmental conditions and mediate changes in immune function, resource allocation and tissue repair. Thus, changes in glucocorticoid hormone concentrations might mediate individual variation in investment in resistance versus tolerance. In this study, we experimentally increased glucocorticoid concentrations in red-winged blackbirds ( Agelaius phoeniceus) that were naturally infected with haemosporidian parasites, and assessed changes in resistance and tolerance of infection. Glucocorticoid treatment increased burdens of Plasmodium, the parasite causing avian malaria, but only in the absence of co-infection with another Haemosporidian, Haemoproteus. Thus, glucocorticoids might reduce resistance to infection, but co-infection can mitigate the negative consequences of increased hormone concentrations. Glucocorticoid treatment also decreased tolerance of infection. We found no evidence that the inflammatory immune response or rate of red blood cell production underlie the effects of glucocorticoids on resistance and tolerance. Our findings suggest that exogenous glucocorticoids can increase the costs of haemosporidian infections by both increasing parasite numbers and reducing an individual's ability to cope with infection. These effects could scale up to impact populations of both host and parasite.

113 Analyzing conflicts between biological and economic efficiencies of beef production without mature cows.

Confounding interests between biological and economic efficiencies of the All Heifer, No Cow (AHNC) beef production system makes system evaluation difficult. In a conventional cow/calf system, emphasis is placed on reproduction, longevity, and maternal behavior with the goal of achieving a cow that successfully breeds back and consistently weans a healthy calf each year. With AHNC, calving ease and carcass quality are emphasized. In the AHNC system, yearling heifers are inseminated with sexed semen to produce primarily females; calves are weaned 3 months after parturition; heifers are finished on a high concentrate diet; and are harvested before 30 months of age. By eliminating the mature cowherd, every animal in the enterprise is growing, offering improved biological efficiency. However, the reduction in feed use does not necessarily equate with economic efficiency. The carcasses produced are high marbling, but payment does not always reflect quality due to premature bone ossification caused by increased hormone concentrations during pregnancy. A model was developed using system dynamics methodology to simulate an AHNC production system. The objective was to increase understanding of interactions and trade-offs between biological and economic efficiencies in the AHNC system. Biological efficiency was considered as lifetime kg of TDN (input) per kg of hot carcass weight produced (output). Profitability was evaluated using net income. The model was calibrated using data from the period 2013 to 2017 collected from the management of an AHNC herd. Efficiency was evaluated by changing the age at harvest and adjusting diet type. Profit leverage points were identified by changing selected variables ±10 % from the observed values while all other variables were held constant. Net income was sensitive to the percent female calves born; a greater number of females coincide with greater profitability. Results suggested AHNC could be managed to balance biological and economic efficiency.

Heterogeneous hCG and hMG commercial preparations result in different intracellular signalling but induce a similar long-term progesterone response in vitro

Are four urinary hCG/menotropin (hMG) and one recombinant preparation characterized by different molecular features and do they mediate specific intracellular signaling and steroidogenesis? hCG and hMG preparations have heterogeneous compositions and mediate preparation-specific cell signaling and early steroidogenesis, although similar progesterone plateau levels are achieved in 24 h-treated human primary granulosa cells in vitro. hCG is the pregnancy hormone marketed as a drug for ARTs to induce final oocyte maturation and ovulation, and to support FSH action. Several hCG formulations are commercially available, differing in source, purification methods and biochemical composition. Commercial hCG preparations for ART or research purposes were compared in vitro. The different preparations were quantified by immunoassay with calibration against the hCG standard (Fifth IS; NIBSC 07/364). Immunoreactivity patterns, isoelectric points and oligosaccharide contents of hCGs were evaluated using reducing and non-reducing Western blotting, capillary isoelectric-focusing immunoassay and lectin-ELISA, respectively. Functional studies were performed in order to evaluate intracellular and total cAMP, progesterone production and β-arrestin 2 recruitment by ELISA and BRET, in both human primary granulosa lutein cells (hGLC) and luteinizing hormone (LH)/hCG receptor (LHCGR)-transfected HEK293 cells, stimulated by increasing hormone concentrations. Statistical analysis was performed using two-way ANOVA and Bonferroni post-test or Mann-Whitney's U-test as appropriate. Heterogeneous profiles were found among preparations, revealing specific molecular weight patterns (20-75 KDa range), isoelectric points (4.0-9.0 pI range) and lectin binding (P < 0.05; n = 7-10). These drug-specific compositions were linked to different potencies on cAMP production (EC50 1.0-400.0 ng/ml range) and β-arrestin 2 recruitment (EC50 0.03-2.0 μg/ml) in hGLC and transfected HEK293 cells (P < 0.05; n = 3-5). In hGLC, these differences were reflected by preparation-specific 8-h progesterone production although similar plateau levels of progesterone were acheived by 24-h treatment (P ≥ 0.05; n = 3). N/A. The biological activity of commercial hCG/hMG preparations is provided in International Units (IU) by in-vivo bioassay and calibration against an International Standard, although it is an unsuitable unit of measure for in-vitro studies. The re-calibration against recombinant hCG,quantified in grams, is based on the assumption that all of the isoforms and glycosylation variants have similar immunoreactivity. hCG/hMG preparation-specific cell responses in vitro may be proposed to ART patients affected by peculiar ovarian response, such as that caused by polycystic ovary syndrome. Otherwise, all the preparations available for ART may provide a similar clinical outcome in healthy women. This study was supported by a grant of the Italian Ministry of Education, University and Research (PRIN 2015XCR88M). The authors have no conflict of interest.

The Effect of Added Weight on Foot Anthropometry in Pregnant Women and Controls

Foot anthropometry is altered by pregnancy, but it is not known if these changes are due to increased weight or hormonal effects of pregnancy on the body. PURPOSE: The purpose of this study was to examine the effect of added weight on foot anthropometry in pregnant women and never-pregnant controls. METHODS: Fifteen primigravid women and 13 nulliparous controls participated. Controls were matched to the pregnant women based on the pregnant women’s self-reported pre-pregnancy weight. Informed consent was obtained. Data were collected on the pregnant subjects in each trimester and post-partum. Foot length, foot width, arch index, arch height index, arch rigidity index, and arch drop were assessed. To determine the effect of added weight on foot anthropometry, pregnant subjects in their first two trimesters donned a weighted pack on the anterior trunk such that total weight difference from pre-pregnancy weight was 124N, which was based on data from a previous study. Foot measurements were then repeated while the subjects wore this pack. Third trimester subjects did not wear a pack as they were at full-pregnancy weight. For post-partum subjects, their body weight plus the weight of the pack equaled their third trimester weight. For control subjects, their body weight plus the weight of the pack equaled the third trimester weight of the pregnant subject to whom they were matched. A MANOVA was performed with the independent variables of trimester (control, 1st, 2nd, 3rd, and post-partum) and weight condition (natural or weighted). Tukey post-hoc analyses were performed if appropriate (α=0.05). RESULTS: Arch drop increased by 18% (p=0.001) and arch rigidity index decreased by 1% (p=0.002) in the weighted condition compared to the natural condition. Increase in foot length and width and decrease in AHI with added weight was greater in pregnant subjects vs controls, with the change increasing over the course of the pregnancy. (p<0.05). CONCLUSIONS: Adding weight produced significant changes in arch drop and arch rigidity index, although weight plus advancing pregnancy was related to further alterations in foot anthropometry, indicating that other factors, such as increased hormone concentrations, may play a role in foot anthropometry changes in pregnancy.

Effect of kisspeptin challenge on testosterone and inhibin secretion from invitro testicular tissue of adult male rhesus monkey (Macaca mulatta).

Kisspeptin expression has been found in gonads but a direct role of kisspeptin in reproduction is not known. The objective of this study was to find a dose and time related effect of kisspeptin on testicular hormones secretion of adult male rhesus monkey (n=5). Kisspeptin (1, 10, 100, 1000pm) was incubated to a culture of testes (100mg fragments) of male rhesus monkey and medium for hormone (testosterone and inhibin) measurement was collected after 30, 60 and 120min. 10 IU hCG (180min) and 50ng FSH (60 and 120min) were incubated to the culture for checking testicular cells ability to secrete hormones invitro. Kisspeptin did not significantly (P<0.05) increase the testosterone and inhibin levels at any dose. However, one way anova at pooled doses showed an increase in testosterone levels and paired t-test at pooled doses showed inhibin decrease after 120min of incubation suggesting an independent effect of time. hCG and FSH significantly (P<0.05) increased hormone concentration compared to the basal groups. We concluded that kisspeptin has no role in testicular regulation related to testosterone and inhibin release but kisspeptin may have other roles in testicular regulation.

Hormone levels predict individual differences in reproductive success in a passerine bird

Hormones mediate major physiological and behavioural components of the reproductive phenotype of individuals. To understand basic evolutionary processes in the hormonal regulation of reproductive traits, we need to know whether, and during which reproductive phases, individual variation in hormone concentrations relates to fitness in natural populations. We related circulating concentrations of prolactin and corticosterone to parental behaviour and reproductive success during both the pre-breeding and the chick-rearing stages in both individuals of pairs of free-living house sparrows, Passer domesticus. Prolactin and baseline corticosterone concentrations in pre-breeding females, and prolactin concentrations in pre-breeding males, predicted total number of fledglings. When the strong effect of lay date on total fledgling number was corrected for, only pre-breeding baseline corticosterone, but not prolactin, was negatively correlated with the reproductive success of females. During the breeding season, nestling provisioning rates of both sexes were negatively correlated with stress-induced corticosterone levels. Lastly, individuals of both sexes with low baseline corticosterone before and high baseline corticosterone during breeding raised the most offspring, suggesting that either the plasticity of this trait contributes to reproductive success or that high parental effort leads to increased hormone concentrations. Thus hormone concentrations both before and during breeding, as well as their seasonal dynamics, predict reproductive success, suggesting that individual variation in absolute concentrations and in plasticity is functionally significant, and, if heritable, may be a target of selection.

Incidence of hypertrophic pulmonary osteoarthropathy associated with primary lung cancer

Although the association of hypertrophic pulmonary osteoarthropathy (HPO) with lung cancer was investigated in the 1960s, the recent incidence of clinically apparent HPO is not known. Data from a large series of patients with lung cancer were analysed, in order to assess the incidence of possible HPO, based on bone scintigraphy, as well as the incidence of clinically confirmed HPO. The clinical features of confirmed HPO were also evaluated. The medical records of patients admitted with lung cancer between January 1986 and August 2004 were reviewed. Bone scintigraphy showing symmetrical, abnormally high uptake in joints and/or long bones was considered to be suggestive of HPO. Patients who also had finger clubbing and joint pain were considered to have a confirmed diagnosis of HPO. Clinical histories and hormone levels were then investigated in these patients, to identify possible causal factors. Among the 1226 lung cancer patients, 55 (4.5%) demonstrated abnormally high uptake on bone scintigraphy, suggesting possible HPO. Ten (0.8%) patients had clubbed fingers and joint pain and were eventually confirmed as having HPO. Serum hormone concentrations were abnormally high in the patients with confirmed HPO. This retrospective study indicated that 4.5% of lung cancer patients showed findings suggestive of HPO, a frequency similar to that reported previously. However, patients with HPO rarely showed the complete triad of signs. Although increased hormone concentrations may have caused the HPO, further investigation is required to confirm this.

Early maternal deprivation and neonatal single administration with a cannabinoid agonist induce long-term sex-dependent psychoimmunoendocrine effects in adolescent rats

Maternal deprivation [24h on postnatal day 9] might represent an animal model of schizophrenia and behavioural and neurochemical alterations observed in adulthood may be mediated by hippocampal impairments induced by abnormally increased glucocorticoids due to neonatal stress. We aimed to provide new data for psychoimmunoendocrine characterization of this animal model by evaluating its effects in adolescent rats of both genders. In previous studies we found that cannabinoid compounds counteracted the enhanced impulsivity of maternally deprived animals and that the cannabinoid receptor agonist WIN 55,212-2 showed neuroprotective properties in neonatal rats. So, we hypothesised that this compound could counteract at least some of the detrimental effects that we expected to find in maternally deprived animals. Accordingly, the drug was administered immediately after the maternal deprivation period. Maternally deprived males showed significantly decreased motor activity in the holeboard and the plus-maze. The cannabinoid agonist induced, exclusively in males, a significant anxiogenic-like effect, which was reversed by maternal deprivation. In the forced swimming test, both treatments independently induced depressive-like responses. Maternal deprivation reduced immunological function whereas the drug exerted tissue-dependent effects on the immune parameters analysed. Maternally deprived females showed reduced corticosterone levels whereas the cannabinoid agonist increased hormone concentration in all groups. In general, the results show detrimental effects of both treatments as well as intriguing interactions, notably in relation to emotional behaviour and certain immunological responses.

Effects of breakfast with different calorigenic amounts on blood glucose, insulin and glucagon levels

This study was aimed to investigate the relationship between breakfast and serum glucose, insulin and glucagon concentrations in order to establish a model breakfast appropriate for Chinese. Twenty-four volunteers were randomly assigned to four study groups: high carbohydrate breakfast, high fat and protein breakfast, the typical breakfast and fasting. Each subject had serum and urine samples collected while fasting and at 1,2 and 3.5 hours following the meal. The concentration of serum glucose, insulin and glucagon was measured. The levels of serum glucose in group A, B and C differed significantly at 1 and 2 hour after meal compared to those at fasting (P<0.05). The serum glucose in group A increased insignificantly after meal. The serum insulin levels were in group A,B and C significant different compared with control group (P<0.05). Those peaked at 1 hour after meal, with group C rising the furthest. Compared with the fasting group, the serum glucagons rose and maintained the increase after breakfast in group A,B and C (P<0.05). The data suggested that various diets with different calorigenic amounts increased hormone concentration to various extents. We found that a breakfast rich in carbohydrates could maintain proper blood glucose level.

Genes for Hormone Biosynthesis and Regulation Are Highly Expressed in Citrus Flowers Infected with the Fungus Colletotrichum acutatum, Causal Agent of Postbloom Fruit Drop

Colletotrichum acutatum J. H. Simmonds infects citrus flower petals, causing brownish lesions, young fruit drop, production of persistent calyces, and leaf distortion. This suggests that hormones may be involved in symptom development. To identify the types of hormones, cDNA clones encoding proteins related to ethylene and jasmonate (JA) biosynthesis, indole-3-acetic acid (IAA) regulation, cell-wall modification, signal transduction, or fruit ripening were used to examine differential gene expressions in calamondin (Citrus madurensis Lour) and/or `Valencia' sweet orange (Citrus sinensis Osbeck) after C. acutatum infection. Northern-blot analyses revealed that the genes encoding 1-aminocyclopropane-1-carboxylate (ACC) oxidase and 12-oxophytodienoate required for ethylene and JA biosynthesis, respectively, were highly up-regulated in both citrus species. Both gene transcripts increased markedly in petals, young fruit and stigmas, but not in calyces. The transcripts of the genes encoding IAA glucose transferase and auxin-responsive GH3-like protein, but not IAA amino acid hydrolyase, also markedly increased in both species 5 days after inoculation. The expansin and chitinase genes were slightly up-regulated, whereas the senescence-induced nuclease and ß-galactosidase genes were down-regulated in calamondin. No differential expression of transcripts was detected for the genes encoding expansin, polygalacturonase, and serine-threonine kinase in sweet orange. As compared to the water controls, infection of C. acutatum increased ethylene and IAA levels by 3- and 140-fold. In contrast, abscisic acid (ABA) levels were not significantly changed. Collectively, the results indicate that infection by C. acutatum of citrus flowers triggered differential gene expressions, mainly associated with IAA, ethylene, and JA production and regulation, and increased hormone concentrations, consistent with the hypothesis of the involvement of phytohormones in postbloom fruit drop.

Endogenous sex hormones and breast cancer in postmenopausal women: reanalysis of nine prospective studies.

Reproductive and hormonal factors are involved in the etiology of breast cancer, but there are only a few prospective studies on endogenous sex hormone levels and breast cancer risk. We reanalyzed the worldwide data from prospective studies to examine the relationship between the levels of endogenous sex hormones and breast cancer risk in postmenopausal women. We analyzed the individual data from nine prospective studies on 663 women who developed breast cancer and 1765 women who did not. None of the women was taking exogenous sex hormones when their blood was collected to determine hormone levels. The relative risks (RRs) for breast cancer associated with increasing hormone concentrations were estimated by conditional logistic regression on case-control sets matched within each study. Linear trends and heterogeneity of RRs were assessed by two-sided tests or chi-square tests, as appropriate. The risk for breast cancer increased statistically significantly with increasing concentrations of all sex hormones examined: total estradiol, free estradiol, non-sex hormone-binding globulin (SHBG)-bound estradiol (which comprises free and albumin-bound estradiol), estrone, estrone sulfate, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and testosterone. The RRs for women with increasing quintiles of estradiol concentrations, relative to the lowest quintile, were 1.42 (95% confidence interval [CI] = 1.04 to 1.95), 1.21 (95% CI = 0.89 to 1.66), 1.80 (95% CI = 1.33 to 2.43), and 2.00 (95% CI = 1.47 to 2.71; P(trend)<.001); the RRs for women with increasing quintiles of free estradiol were 1.38 (95% CI = 0.94 to 2.03), 1.84 (95% CI = 1.24 to 2.74), 2.24 (95% CI = 1.53 to 3.27), and 2.58 (95% CI = 1.76 to 3.78; P(trend)<.001). The magnitudes of risk associated with the other estrogens and with the androgens were similar. SHBG was associated with a decrease in breast cancer risk (P(trend) =.041). The increases in risk associated with increased levels of all sex hormones remained after subjects who were diagnosed with breast cancer within 2 years of blood collection were excluded from the analysis. Levels of endogenous sex hormones are strongly associated with breast cancer risk in postmenopausal women.

Insulin permeability across an in vitro dynamic model of endothelium.

Endothelium insulin permeability was investigated using in vitro, dynamic culture of endothelial cells. Endothelial cells were cultured in a hollow fiber apparatus and continuously exposed to a flow. Transendothelial electrical resistance and permeability to [14C]sucrose and [14C]inulin were used to monitor the integrity of the endothelial monolayer. Under these experimental conditions, measurements of insulin permeability, investigated at increasing hormone concentrations, suggested that the predominant transendothelial insulin fluxes were attributable to bidirectional convective transport rather than to a saturable transport mechanism, in agreement with in vivo experiment results published earlier. Analytical determinations of insulin catabolism demonstrated a low percent of insulin degradation by the endothelium, leading to production of insulin metabolites qualitatively identical to those produced by human monocytes. The findings of this paper indicated that (a) insulin crosses the endothelial monolayer by paracellular "leak" and endothelial insulin receptors have a minor (if any) role in insulin transport; (b) degradation of the hormone by BAEC is minimal; (c) the in vitro, dynamic culture of endothelial cells presented here should represent a valuable transport model system to study permeability mechanisms of insulin and many other drugs.

Effect of ACTH-challenge on progesterone and cortisol levels in ovariectomised repeat breeder heifers

In order to investigate the potential influence of stress as a component of the repeat breeding syndrome, the adrenocortical capacity for steroid production was evaluated in ovariectomised dairy heifers. In repeat breeder heifers (RBH), marginally elevated plasma progesterone levels during oestrus, so-called suprabasal progesterone levels, have earlier been measured and are believed to impair fertility. The aim was to distinguish if this progesterone could be of extra-gonadal or in this case, adrenal origin. Baseline levels of plasma cortisol and progesterone were determined as well as the corresponding response after induced acute stress in the form of an adrenocorticotropin (ACTH)-challenge. Comparisons were made between strictly selected RBH, n=5 and virgin heifers (VH), n=5 of the Swedish Red and White breed. The heifers were used as their own pre-challenge controls in a 2-day trial. On the control day, saline was injected i.v. and on the treatment day, a synthetic analogue of ACTH (60 μg Synachten®). Via a jugular vein catheter, blood samples were collected every 30 min for 6 h each day of the experiment. Analyses for plasma progesterone and cortisol were made. RBH had a significantly higher ( P<0.01) pretreatment baseline cortisol level (10.1±2.3 nmol l −1) than VH (2.6±0.2 nmol l −1). Moreover, the cortisol response after stimuli was stronger in RBH than VH, especially concerning total hormone production ( P<0.001), but there was also a tendency towards higher peak values ( P=0.06) and longer duration of significantly increased hormone concentrations ( P=0.08). Progesterone concentrations, however, did not differ between the groups. Both baseline levels ( P=0.25) and posttreatment production ( P=0.45) were of the same magnitude in RBH and VH. In conclusion, the study could not confirm that suprabasal progesterone concentrations during oestrus in RBH derive from the adrenal glands. Still, apparent differences were found in adrenocortical activity when ovariectomised heifers, VH and RBH, were subjected to an ACTH-challenge. It is suggested that a sustained adrenal stimulation associated with environmental or social stress could be one factor in the repeat breeding syndrome.

Atrial natriuretic factor after cardiac surgery with cardiopulmonary bypass in children

To determine circulating atrial natriuretic factor (ANF) concentrations in the postoperative state and to define potential hemodynamic determinants of regional plasma ANF concentrations. Cohort study. Pediatric ICU in a university hospital. Twenty-two children, mean age 4.2 yrs (range 0.9 to 13.5), were studied 18 hrs after corrective surgery on cardiopulmonary bypass. The underlying cardiac malformations were ventricular septum defect (n = 5), transposition of great arteries (n = 5), tetralogy of Fallot (n = 4), pulmonary stenosis (n = 3), and miscellaneous (n = 5). In addition to the commonly monitored variables in postoperative cardiac patients, blood volume was estimated by the 125I albumin method, and plasma samples for radioimmunoassay determination of ANF concentrations were taken simultaneously from indwelling catheters. Compared with normal age-matched values, plasma ANF concentrations were increased in all patients, with values tending to be highest in the left atrium, followed by systemic artery, superior vena cava, and pulmonary artery (345 +/- 158, 333 +/- 169, 311 +/- 154, and 272 +/- 160 pg/mL, respectively [mean +/- SD; NS]). Simple regression analysis demonstrated a moderate correlation between blood volume and the concentration of ANF in the superior vena cava (p less than .05). Stepwise multivariate analysis showed no significant independent predictor of plasma ANF concentrations. Plasma ANF concentrations are increased after open-heart surgery in children, with moderate direct correlation to blood volume. The wide scatter of increased hormone concentrations may be explained by the many factors known to influence circulating ANF concentrations, such as age, underlying disease, cardiovascular state, and drugs.

A longitudinal study of circulating progesterone, oestradiol, hCG and hPL during pregnancy in type 1 diabetic mothers.

Serum progesterone, oestradiol, human chorionic gonadotrophin (hCG) and human placental lactogen (hPL) were determined serially throughout 27 pregnancies in insulin-dependent diabetic patients from Newcastle (UK), 15 such patients from Stockholm (Sweden) and in 69 normal women having uncomplicated pregnancies. Mean progesterone, oestradiol and hCG concentrations were somewhat higher in the diabetic women during the third trimester but hPL values were not different from normal. The increased hormone concentrations did not relate to the increased birthweights or placental weights in the diabetic women. It is suggested that the usual physiological endocrine changes during normal pregnancy are relatively undisturbed by insulin-dependent diabetes or the degree of diabetes control achieved.

Inhibition of cyclic 3',5' monophosphate synthesis in rat testis by L-triiodothyronine.

Cytosolic adenylate cyclase activity from rat seminiferous tubules is inhibited by L-triiodothyronine (L-T3). In a typical dose-response curve, using Mn-ATP as substrate, no effect is observed at 10(-10) M L-T3; about 15 to 25% inhibition is found in the range between 10(-9) and 10(-6) M L-T3 and finally a sharp enzyme inhibition is evident at increasing hormone concentrations from 10(-6) to 10(-4) M. Incubation of decapsulated testes with L-T3 leads to a decrease of intracellular cyclic AMP levels. Dose-response relationships for such effect are similar to those found for adenylate cyclase activity. In this case a clear response is observed at 10(-8) M L-T3.

Influence of Lithium on Cyclic AMP Accumulation in Isolated Rat Fat Cells

Lithium inhibits in vitro as well as in vivo several hormone-stimulated adenylate cyclases. The aim of this study was to investigate the mechanism by which lithium inhibits adenylate cyclase in vitro. It was found that lithium inhibited both the norepinephrine- and the glucagon-induced cAMP accumulation in rat fat cells at lithium concentrations above 10 mM. The basal cAMP content was unaffected even at 40 mM of lithium. The inhibitory action was time-dependent and reversible, indicating an intracellular site of action. Lithium inhibited both norepinephrine- and glucagon-stimulated cAMP accumulation in a mainly non-competitive way, but the inhibitory effect decreased with increasing hormone concentrations. In accordance, lithium and propranolol had a supraadditive effect on norepinephrine-induced cAMP accumulation. It is suggested that lithium affects both the hormone-receptor binding as well as the transfer of the hormonal stimulus by an intracellular site of action.