S-carboxymethylcysteine inhibits adherence of Streptococcus pneumoniae to human alveolar epithelial cells

Streptococcus pneumoniae is a major pathogen of respiratory infections that utilizes platelet-activating factor receptor (PAFR) for firm adherence to host cells. The mucolytic agent S-carboxymethylcysteine (S-CMC) has been shown to exert inhibitory effects against infection by several respiratory pathogens including S. pneumoniae in vitro and in vivo. Moreover, clinical studies have implicated the benefits of S-CMC in preventing exacerbation of chronic obstructive pulmonary disease, which is considered to be related to respiratory infections. In this study, to assess whether the potency of S-CMC is attributable to inhibition of pneumococcal adherence to host cells, an alveolar epithelial cell line stimulated with interleukin-1α was used as a model of inflamed epithelial cells. Despite upregulation of PAFR by inflammatory activation, treatment with S-CMC efficiently inhibited pneumococcal adherence to host epithelial cells. In order to gain insight into the inhibitory mechanism, the effects of S-CMC on PAFR expression were also investigated. Following treatment with S-CMC, PAFR expression was reduced at both mRNA and post-transcriptional levels. Interestingly, S-CMC was also effective in inhibiting pneumococcal adherence to cells transfected with PAFR small interfering RNAs. These results indicate S-CMC as a probable inhibitor targeting numerous epithelial receptors that interact with S. pneumoniae.

Assembly mechanism of FCT region type 1 pili in serotype M6 Streptococcus pyogenes

The human pathogen Streptococcus pyogenes produces diverse pili depending on the serotype. We investigated the assembly mechanism of FCT type 1 pili in a serotype M6 strain. The pili were found to be assembled from two precursor proteins, the backbone protein T6 and ancillary protein FctX, and anchored to the cell wall in a manner that requires both a housekeeping sortase enzyme (SrtA) and pilus-associated sortase enzyme (SrtB). SrtB is primarily required for efficient formation of the T6 and FctX complex and subsequent polymerization of T6, whereas proper anchoring of the pili to the cell wall is mainly mediated by SrtA. Because motifs essential for polymerization of pilus backbone proteins in other Gram-positive bacteria are not present in T6, we sought to identify the functional residues involved in this process. Our results showed that T6 encompasses the novel VAKS pilin motif conserved in streptococcal T6 homologues and that the lysine residue (Lys-175) within the motif and cell wall sorting signal of T6 are prerequisites for isopeptide linkage of T6 molecules. Because Lys-175 and the cell wall sorting signal of FctX are indispensable for substantial incorporation of FctX into the T6 pilus shaft, FctX is suggested to be located at the pilus tip, which was also implied by immunogold electron microscopy findings. Thus, the elaborate assembly of FCT type 1 pili is potentially organized by sortase-mediated cross-linking between sorting signals and the amino group of Lys-175 positioned in the VAKS motif of T6, thereby displaying T6 and FctX in a temporospatial manner.

Streptolysin S contributes to group A streptococcal translocation across an epithelial barrier

Group A Streptococcus pyogenes (GAS) is a human pathogen that causes local suppurative infections and severe invasive diseases. Systemic dissemination of GAS is initiated by bacterial penetration of the epithelial barrier of the pharynx or damaged skin. To gain insight into the mechanism by which GAS penetrates the epithelial barrier, we sought to identify both bacterial and host factors involved in the process. Screening of a transposon mutant library of a clinical GAS isolate recovered from an invasive episode allowed identification of streptolysin S (SLS) as a novel factor that facilitates the translocation of GAS. Of note, the wild type strain efficiently translocated across the epithelial monolayer, accompanied by a decrease in transepithelial electrical resistance and cleavage of transmembrane junctional proteins, including occludin and E-cadherin. Loss of integrity of intercellular junctions was inhibited after infection with a deletion mutant of the sagA gene encoding SLS, as compared with those infected with the wild type strain. Interestingly, following GAS infection, calpain was recruited to the plasma membrane along with E-cadherin. Moreover, bacterial translocation and destabilization of the junctions were partially inhibited by a pharmacological calpain inhibitor or genetic interference with calpain. Our data indicate a potential function of SLS that facilitates GAS invasion into deeper tissues via degradation of epithelial intercellular junctions in concert with the host cysteine protease calpain.

Pili of oral Streptococcus sanguinis bind to fibronectin and contribute to cell adhesion

Streptococcus sanguinis is a predominant bacterium in the human oral cavity and occasionally causes infective endocarditis. We identified a unique cell surface polymeric structure named pili in this species and investigated its functions in regard to its potential virulence. Pili of S. sanguinis strain SK36 were shown to be composed of three distinctive pilus proteins (PilA, PilB, and PilC), and a pili-deficient mutant demonstrated reduced bacterial adherence to HeLa and human oral epithelial cells. PilC showed a binding ability to fibronectin, suggesting that pili are involved in colonization by this species. In addition, ATCC10556, a standard S. sanguinis strain, was unable to produce pili due to defective pilus genes, which indicates a diversity of pilus expression among various S. sanguinis strains.

The mode of the antifungal activity of gemini-pyridinium salt against yeast

The gemini quaternary salt (gemini-QUAT) containing two pyridinium residues per molecule, 3,3'-(2,7-dioxaoctane) bis (1-decylpyridinium bromide) (3DOBP-4,10), exerted fungicidal activity against Saccharomyces cerevisiae accompanied by respiration inhibition and the cytoplasmic material leakage of ATP, magnesium, and potassium ions. We previously found that gemini-QUAT exerted bacterioclastic action against Escherichia coli by causing the rapid and abundant leakage of turbid materials from the cells. In addition, the first stage of the bacterioclastic action was the leakage of magnesium ions, outer membrane protein E, ATP, and lipopolysaccharides. Here, we investigated how the gemini-QUAT 3DOBP-4,10 exerts fungicidal action against S. cerevislae. The results showed that that > or = 0.4 microM 3DOBP-4,10 stopped respiration and that > or = 3.0, 1.0 and 1.0 microM caused the leakage of cytoplasmic components ATP, magnesium and potassium ions, respectively. Scanning and transmission electron micrographs showed a preserved cell wall structure, whereas intracellular organelles were destroyed in cells incubated with 3DOBP-4,10. We postulated that 3DOBP-4,10 exerts its fungicidal action against S. cerevisiae not through cell wall destruction and protein leakage, but rather by penetrating the cell wall and disrupting the membranes of organelles.

Correlation between the bacterioclastic action of a bis-quaternary ammonium compound and outer membrane proteins

Bis-quaternary ammonium compounds (bis-QACs) have the ability to cause a rapid and abundant leakage of the turbid materials from cells, and such a bacterioclastic ability leads to a potent bactericidal activity. In order to clarify the detailed mechanism of the bactericidal action of bis-QACs, the correlation between the bacterioclastic action of 4,4'-(1,6-hexamethylenedithio)bis(1-octylpyridinium bromide) (4DTBP-6,8) and the leakage of outer membrane pore protein E (OmpE) was investigated. Using the antiserum against a fusion protein consisting of GST and the OmpE protein of Escherichia coli encoded by the ompE gene, it was seen that the leakage of OmpE from E. coli cells was caused by treatment with low concentrations (much lower than the critical vesiculation concentration) of 4DTBP-6,8. Furthermore, it was confirmed that 4DTBP-6,8 caused an increase in the turbidity of the cell suspension of Klebsiella pneumoniae, Salmonella typhimurium and Serratia marcescences, and led to the leakage of several proteins which have a high percentage of homology with OmpE of E. coll. By immunoelectron microscopy investigation, it was revealed that the vesiculation from E. coli treated with 4DTBP-6,8 contains OmpE. In addition, the bacteriolytic action of 4DTBP-6,8 was investigated. The results suggested that the lysis of cells by bis-QACs was not an enzymatic action such as that by autolysin but a physical bacterioclastic action. Judging from these results, it is suggested that the leakage of OmpE is one of the major bacterioclastic actions of bis-QACs, and deals the bacterial cells a fatal blow.

Construction of a leftover bath water model for microbial testing

In this study, in order to construct a model of leftover bath water, we analyzed one hundred samples of used bath water samples which were provided by twenty-eight volunteer families. It appeared that the number of detected bacteria from such bath water was correlated closely with the number of bathers. Moreover, the pH, acidity, chemical oxygen demand (COD), ion, protein content of the leftover bath water were measured. The number of bathers had no connection with the pH, acidity, COD, and ion content of the leftover bath water. However, the protein content of the bath water correlated with the number of detected bacteria. Based on these results, the model of leftover bath water was constructed. Achromobacter xylosoxidans, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa were incubated with the model bath water as indices of bath water contamination. The number of incubated viable cells in the model bath water increased with increasing concentrations of casamino acid. Consequently, it was suggested that varying the concentration of casamino acid based on family size or contamination would be necessary in the efficient use of the constructed model of leftover bath water for microbial testing.

Synthesis and biological properties of gemini quaternary ammonium compounds, 5,5'-[2,2'-(alpha,omega-polymethylnedicarbonyldioxy)diethyl]bis-(3-alkyl-4-methylthiazolium iodide) and 5,5'-[2,2'-(p-phenylenedicarbonyldioxy)diethyl]bis(3-alkyl-4-methylthiazolium bromide)

We synthesized gemini quaternary ammonium compounds (gemini QACs) having two thiazolium moieties in a molecule, 5,5'-[2,2'-(alpha,omega-polymethylnedicarbonyldioxy)diethyl]bis(3-alkyl-4-methylthiazolium iodide) (5DEBT-m,n), on which the carbon number of the methylene chain linking the two thiazoles (m) is 2, 6 or 8 and that of the alkyl group (n) is 8, 10, 12, 14 or 16. 5,5'-[2,2'-(p-Phenylenedicarbonyldioxy)diethyl]bis(3-alkyl-4-methylthiazolium bromide) (5DEBT-P,n) was then synthesized, which is composed of a p-phenylene as the methylene spacer. For five gemini QAC series, in addition to the previously described 5DEBT-4,n to the four new compound series, their antimicrobial activities were determined. 5DEBT-m,10 and -P,10 exhibited a wide and strong bacteriostatic activity against gram-negative and -positive bacteria, fungi and then yeast in comparison with N-tetradecyl-5-(2-hydroxyethyl)-4-methylthiazolium iodide as a mono-QAC. The bactericidal activity of the 5DEBT series against Escherichia coli IFO 12713 and Staphylococcus aureus IFO 12732 was investigated on the basis of the effects of their alkyl chain length and their molecular hydrophobicity. It was found that the effect of theses factors on their activity significantly changes by the difference between the gram-negative and -positive bacteria. Although against the gram-negative bacterium, the change in the activity due to extension of the alkyl group for each compound affected the kind of methylene spacer, against the gram-positive bacterium, it was almost equal in spite of the methylene spacer. This result could be responsible for the bactericidal mechanism of the gemini QACs being influenced by the diversity of the steric structure participating in the methylene chain length and by the bacterium cell surface hydrophobicity.

Saireito (a Chinese herbal drug)-stimulated secretion and synthesis of pituitary ACTH are mediated by hypothalamic corticotropin-releasing factor

Administration of Saireito, a Saiko agent (a Chinese herbal drug), via a stomach cannula stimulates ACTH release and proopiomelanocortin, the precursor for ACTH, gene expression in the rat anterior pituitary. To study whether Saireito-stimulated secretion and synthesis of ACTH are mediated by hypothalamic corticotropin-releasing factor (CRF), we examined the effect of passive immunization of endogenous CRF by i.v. administration of CRF antiserum on Saireito-increased plasma ACTH levels and proopiomelanocortin gene expression in the rat anterior pituitary, under pentobarbital anesthesia. CRF antiserum inhibited Saireito-induced plasma ACTH levels and proopiomelanocortin mRNA levels in the anterior pituitary. This result indicates that Saireito stimulates CRF neurons to increase CRF release, which stimulates secretion and synthesis of ACTH.

Stimulatory effect of Saireito on proopiomelanocortin gene expression in the rat anterior pituitary gland

The effect of administration of Saireito, a Saiko agent, via a stomach cannula on adrenocorticotropin (ACTH) release and gene expression of proopiomelanocortin (POMC), the precursor for ACTH, in the anterior pituitary, as well as on the corticotropin-releasing factor (CRF) in the hypothalamus, was examined in pentobarbital anesthetized rats. Saireito decreased the hypothalamic CRF level due to an early release of CRF and stimulated ACTH release and POMC gene expression but did not increase CRF gene expression. These results suggest that Saireito does not stimulate CRF gene expression, although it does stimulate CRF release, which in turn stimulates POMC gene expression in the anterior pituitary and ACTH release.

Neuropeptide Y increases the corticotropin-releasing factor messenger ribonucleic acid level in the rat hypothalamus

Neuropeptide Y (NPY) has a stimulatory effect on adrenocorticotropin (ACTH) and corticotropin-releasing factor (CRF) release. In the present study, to investigate the effect of NPY on CRF synthesis, the effect of centrally administered NPY on CRF messenger RNA (mRNA) levels in rat hypothalamus was examined under pentobarbital anesthesia. The administration of 0.01, 0.1 and 1 nmol of NPY into the lateral ventricle dose-dependently Increased the plasma ACTH levels, as well as the levels of proopiomelanocortin mRNA in the anterior pituitary. The CRF mRNA level in the hypothalamus also increased after administration of 0.1 and 1 nmol of NPY in a dose-dependent manner. The administration of 3 nmol of phentolamine or propranolol failed to block 0.1 nmol NPY-induced ACTH release or 1 nmol NPY-stimulated CRF mRNA levels in the hypothalamus. These results Indicate that the central administration of NPY increases the CRF mRNA levels in the hypothalamus and the probable CRF release, which increases the proopiomelanocortin mRNA levels and ACTH secretion in the anterior pituitary. Therefore, NPY seems to play a physiological role in the regulation of the release and synthesis of CRF in the hypothalamus.

The role of corticotropin-releasing factor and vasopressin in hypoglycemia-induced proopiomelanocortin gene expression in the rat anterior pituitary gland

In this study, we examined the effect of passive immunization of endogenous corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) on hypoglycemia-induced adrenocorticotropic hormone (ACTH) secretion and determined proopiomelanocortin messenger RNA (POMC mRNA) levels in the anterior pituitary as well as hypothalamic CRF mRNA levels in pentobarbital anesthetized rats. The response of plasma ACTH to hypoglycemia was partially inhibited by the administration of CRF-antiserum (CRF-As) or AVP-antiserum (AVP-As) alone, but was found to be completely abolished by the administration of CRF-As + AVP-As as compared to the response in normal rabbit serum-treated rats. The hypoglycemia-induced POMC mRNA level in the anterior pituitary was completely inhibited by the administration of CRF-As alone and CRF-As + AVP-As, but was not inhibited by AVP-As alone as compared to the response in normal rabbit serum-treated rats. The administration of CRF-As and/or AVP-As did not affect hypoglycemia-induced CRF mRNA levels in the hypothalamus. These results indicate that the synergistic effect of CRF and AVP is important for hypoglycemia-induced ACTH secretion, but CRF is essential and indispensable for hypoglycemia-induced POMC gene expression in the anterior pituitary (AP).

Beta-endorphin inhibits hypoglycemia-induced gene expression of corticotropin-releasing factor in the rat hypothalamus

Endogenous opioid peptides have a role in the regulation of the hypothalamic-pituitary-adrenal axis. Recently, beta-endorphin (EP) has been thought to inhibit CRF release in vivo and in vitro. In the present study we examined the effects of central administration of EP on ACTH secretion and gene expression of both CRF in the hypothalamus and POMC in the anterior pituitary gland (AP) during basal and insulin-induced hypoglycemia in pentobarbital-anesthetized rats. Administration of EP in the lateral ventricle decreased basal CRF levels in the median eminence and inhibited basal and hypoglycemia-induced ACTH secretion in a dose-dependent manner. Hypoglycemia-induced POMC mRNA levels in the AP and CRF mRNA levels in the hypothalamus were also dose-dependently inhibited by the administration of EP. The inhibitory effect of EP was reversed by naloxone. These results suggest that 1) central administration of EP acts through the opioid receptor to inhibit hypoglycemia-induced CRF gene expression in the hypothalamus and CRF release, which results in a decrease in ACTH secretion and POMC mRNA levels in the AP; and 2) the active site of EP is the CRF neuron in the paraventricular nucleus.

Hypothalamic corticotropin-releasing hormone (CRH) secretion into hypophysial portal blood is regulated by cutaneous sensory stimulation in anesthetized rats

The effects of noxious and non-noxious mechanical stimulation of various segmental skin areas (face, forelimb and forepaw, abdomen, hindlimb and hindpaw) on the secretion of immunoreactive corticotropin-releasing hormone (iCRH) from the hypothalamus into hypophysial portal blood was examined in artificially ventilated rats under halothane anesthesia. Secretion of iCRH was calculated from the iCRH concentration in hypophysial portal plasma and the plasma flow rate. Noxious mechanical stimulation of the skin was delivered by pinching using surgical clamps, while non-noxious mechanical stimulation was provided by brushing with tooth brushes. Pinching of the bilateral forepaws or hindpaws and brushing of the bilateral hindlimbs for 20 min increased hypothalamic iCRH secretion. In contrast, pinching of the face or abdomen and brushing of the face, forelimbs, or abdomen for 20 min did not significantly influence it. These results indicate that cutaneous mechanical sensory stimulation contributes to the reflex regulation of CRH secretion from the hypothalamus into hypophysial portal blood, and also that this effect is highly dependent on the site of stimulation.

Presence of CRH-binding protein in amniotic fluid and in umbilical cord plasma

CRH-binding protein was present in the amniotic fluid and in the umbilical cord plasma after 15 weeks and 24 weeks of pregnancy, respectively. The size of the CRH-binding protein was similar to that in the peripheral blood from normal subjects. The level of the binding of CRH-binding protein in the umbilical cord plasma during the third trimester of pregnancy was also similar to that in the peripheral blood of neonates and normal adult subjects. The binding of CRH-binding protein was temporarily decreased at 40 weeks of pregnancy. These results indicate that fetal CRH-binding protein seems to be produced at least in the second trimester of pregnancy.

Effects of sex steroids on beta-endorphin release from rat hypothalamus in vitro

The effects of sex steroids on immunoreactive beta-endorphin (EP) release from the rat hypothalamus in vitro were examined using a rat hypothalamic perifusion system and an EP RIA. Testosterone (1-100 ng/ml) and estradiol (10-100 pg/ml) stimulated EP release in a dose-dependent manner. Dehydroepiandrosterone (DHEA, 1-100 ng/ml) dose-dependently inhibited EP release. These results indicate an inverse relationship between the acute effect of gonadal sex steroids and that of adrenal androgen on hypothalamic EP release in vitro.

Angiotensin II increases the corticotropin-releasing factor messenger ribonucleic acid level in the rat hypothalamus

Angiotensin II (AII) has an important role in the regulation of CRF release. In the present study, the effect of centrally administered AII on CRF messenger RNA (mRNA) levels in the rat hypothalamus was examined. Administration of 0.1 nmol and 1 nmol AII into the lateral ventricle increased the levels of plasma ACTH 20 min and 45 min after administration and those of proopiomelanocortin mRNA in the anterior pituitary (AP) and CRF mRNA in the hypothalamus 2 h after administration. On the other hand, ACTH levels in AP and CRF levels in the median eminence temporarily decreased 45 min after the administration of 1 nmol AII, but it returned to the control level at 90 min. Administration of 10 nmol saralacin, an AII antagonist, blocked 1 nmol AII-induced increase in the levels of plasma ACTH, proopiomelanocortin mRNA in AP, and CRF mRNA in the hypothalamus. These results indicate that central administration of AII increases the CRF mRNA level in the hypothalamus in a receptor-specific manner and also increases CRF release. Therefore, AII seems to have an important role in the regulation of the release and synthesis of CRF in the hypothalamus.

Glucocorticoids decrease a binding of corticotropin-releasing hormone-binding protein in human plasma

The binding of CRH-binding protein (CRH-BP) in plasma to labeled human CRH has been examined in patients with hypothalamic-pituitary-adrenal disorders. Compared with that in normal subjects, CRH-BP binding decreased in patients with Cushing's syndrome of pituitary or adrenal origin and in patients who were treated with a high dose of glucocorticoids over a long period of time. On the other hand, CRH-BP binding increased in patients with Addison's disease or hypopituitarism. In patients with Addison's disease, the high level of CRH-BP binding fell to the control level after glucocorticoid replacement. In patients with Cushing's syndrome, CRH-BP binding gradually increased and reached the higher level about 1 yr after surgery. Thereafter, it returned to the control level. There was a good negative correlation between the levels of plasma cortisol and CRH-BP binding in patients with Cushing's syndrome before and after surgery. A Scatchard analysis of CRH-BP binding in patients with Cushing's syndrome and in normal subjects showed that the binding affinity was similar in both groups, but that the number of binding sites was low in patients with Cushing's syndrome. These results suggest that in human plasma, glucocorticoids decrease CRH-BP binding. This seems to be caused by a decrease in the concentration of CRH-BP in the plasma of patients with hypercortisolemia.

Interleukin-1 stimulates corticotropin-releasing factor gene expression in rat hypothalamus

To examine the effect of interleukin-1 (IL-1) on CRF and POMC gene expression, recombinant human IL-1 alpha and -beta were ip injected in rats. The plasma ACTH level showed a dose-related increase at 2 h after the injection of 0.5 and 2 micrograms IL-1 alpha and -beta, and also showed a sustained increase from 1 h until 5 h after the injection of 2 micrograms of IL-1 beta. CRF contents in the medial basal hypothalamus and ACTH contents in the anterior pituitary (AP) decreased at 2 h after the injection of 2 micrograms of IL-1 alpha and -beta, and such decreased levels were maintained until 5 h after the injection of 2 micrograms of IL-1 beta. The levels of CRF mRNA in the hypothalamus and POMC mRNA in AP significantly increased 3 h after the injection of 2 micrograms IL-1 alpha and -beta, and these levels were still higher at 5 h after the injection of 2 micrograms of IL-1 beta compared with those of the control. There was no significant change in the ACTH content and POMC mRNA levels in the intermediate-posterior pituitary or the hypothalamus or in the CRF contents and CRF mRNA levels in the cerebral cortex. These results indicate that acute administration of IL-1 alpha and -beta stimulates gene expression of hypothalamic CRF and CRF release, which causes the stimulation of ACTH release and POMC gene expression in AP.

Corticotropin-releasing factor-binding protein is a glycoprotein

Human corticotropin-releasing factor-binding protein (hCRF-BP), a 38,000 dalton protein, specifically binds hCRF in plasma. CRF-BP-CRF complex adsorbed to concanavalin-A-Sepharose and its Mr decreased after treatment with endoglycosidase H or glycopeptidase A. The binding of CRF-BP to CRF decreased after treatment with endoglycosidase H. These results indicate that the CRF-BP is a glycoprotein that contains asparagine N-linked-type oligosaccharides, and such oligosaccharide chains are important for CRF-BP binding.

Responses to corticotropin-releasing hormone and its bound and free forms in pregnant and nonpregnant women

Plasma CRH levels are considerably higher in women during the third trimester of pregnancy than in non-pregnant women. Most of plasma CRH in pregnant women is bound to CRH-binding protein (CRH-BP). To gain further insight into CRH physiology during pregnancy, we measured the responses of plasma ACTH and cortisol and the changes in bound and free forms of CRH in plasma after human CRH administration (2 micrograms/kg) in five pregnant (39-40 weeks of pregnancy) and five nonpregnant women. The mean basal plasma ACTH and cortisol levels in the pregnant women were higher than those in the nonpregnant women. However, the maximum increments in plasma ACTH and cortisol levels and the integrated ACTH and cortisol responses, after subtraction of the basal levels after CRH administration, were similar in the two groups. The plasma CRH half-time in the pregnant group was similar to that in the nonpregnant group. The mean basal plasma CRH level in the nonpregnant women was 1.5 +/- 0.2 (+/- SE) pmol/L, and that in the pregnant women was 360 +/- 35 pmol/L. On gel filtration chromatography, almost all of the CRH in the plasma was protein bound (320 +/- 30 pmol/L) in the pregnant women; no CRH peaks were detected in nonpregnant women because of the low plasma CRH levels. After CRH administration, the level of the bound form of plasma CRH was highest at 5 min, and then declined to a plateau at 15 min and 30 min in the pregnant women. In the nonpregnant women, protein-bound CRH also was highest at 5 min, but it progressively declined thereafter. The disappearance rate of the bound CRH in plasma from the nonpregnant women was similar to that of the second compartment of the plasma decay curves of the free CRH from both groups. We conclude that the plasma ACTH and cortisol responses to exogenous CRH are similar in pregnant and nonpregnant women, the effect of CRH-BP on the disappearance of plasma CRH is minimal, and plasma CRH-BP in pregnant women has the capacity to bind additional CRH.