We previously reported that immunoreactive corticotropin-releasing hormone (CRH) is present in human placenta and third trimester maternal plasma, and that such material is very similar to rat CRH and the predicted structure of human CRH. We suggested that maternal plasma immunoreactive CRH may be of placental origin. To further investigate this possibility, we measured plasma immunoreactive CRH in women during pregnancy, labor, and delivery and 1 and 2 h postpartum, and in nonpregnant women. Umbilical cord plasma and placental CRH concentrations were also measured. In the first trimester of pregnancy, the mean maternal plasma level was 5.9 +/- 1.0 pg (+/- SEM)/ml (n = 24), not significantly different from that in 10 nonpregnant women (5.8 +/- 0.8 pg/ml). Plasma CRH concentrations progressively increased during pregnancy (second trimester, 35.4 +/- 5.9 pg/ml (n = 39); early third trimester (28-34 weeks), 263 +/- 41 pg/ml (n = 14); late third trimester (35-40 weeks), 800 +/- 163 pg/ml (n = 20)]. There was a significant correlation between maternal plasma CRH levels and weeks of pregnancy. Plasma CRH concentrations were further elevated (2215 +/- 329 pg/ml; n = 9). During early labor, peaked at delivery (4409 +/- 591 pg/ml; n = 28), and declined rapidly after delivery [1 h postpartum, 1042 +/- (353 pg/ml (n = 13); 2 h postpartum, 346 +/- 91 pg/ml (n = 13)]. There was a significant correlation (r = 0.562; P less than 0.01) between matched maternal plasma and placental CRH concentrations. The mean umbilical cord plasma CRH level (50.6 +/- 6.1 pg/ml; n = 28) was much lower than that in the mother at the time of delivery. Umbilical venous plasma CRH levels were significantly greater than those in simultaneously obtained umbilical arterial plasma (70.8 +/- 11.3 and 41.8 +/- 4.9 pg/ml, respectively; n = 11). There was a significant correlation (r = 0.384; P less than 0.05) between maternal and fetal CRH concentrations. Gel filtration of plasma obtained from women during the third trimester, at delivery, and early postpartum and placental extracts revealed two major peaks of immunoreactive CRH: a high mol wt peak and one at the elution position of rat CRH. In contrast, only rat CRH-sized material was detected in plasma from nonpregnant women and umbilical cord plasma. Maternal plasma immunoreactive CRH-sized material stimulated ACTH release from anterior pituitary tissue in a dose-dependent manner and was equipotent with rat CRH.(ABSTRACT TRUNCATED AT 400 WORDS)

We report on PTPN11 (protein-tyrosine phosphatase, nonreceptor type 11) mutation analysis and clinical assessment in 45 patients with Noonan syndrome. Sequence analysis was performed for all of the coding exons 1-15 of PTPN11, revealing a novel 3-bp deletion mutation and 10 recurrent missense mutations in 18 patients. Clinical assessment showed that 1) the growth pattern was similar in mutation-positive and mutation-negative patients, with no significant difference in birth length [-0.6 +/- 2.2 sd (n = 10) vs. -0.6 +/- 1.4 sd (n = 21); P = 0.95], childhood height [-2.6 +/- 1.1 sd (n = 14) vs. -2.1 +/- 1.6 sd (n = 23); P = 0.28], or target height [-0.4 +/- 0.9 sd (n = 14) vs. -0.2 +/- 0.7 sd (n = 17); P = 0.52]; 2) pulmonary valve stenosis was more frequent in mutation-positive patients than in mutation-negative patients (10 of 18 vs. 6 of 27; P = 0.02), as was atrial septal defect (10 of 18 vs. 4 of 27; P = 0.005), whereas hypertrophic cardiomyopathy was present in five mutation-negative patients only; and 3) other features were grossly similar in the prevalence between mutation-positive and mutation-negative patients, but hematological abnormalities, such as bleeding diathesis and juvenile myelomonocytic leukemia, were exclusively present in mutation-positive patients (5 of 18 vs. 0 of 27; P = 0.007). The results suggest that PTPN11 mutations account for approximately 40% of Noonan syndrome patients, as has been reported previously. Furthermore, assessment of clinical features, in conjunction with data reported previously, implies that the type of cardiovascular lesions and the occurrence of hematological abnormalities are different in mutation-positive and mutation-negative patients, whereas the remaining findings are similar in the two groups of patients.

No abstract

Immunoreactive CRH concentrations were determined in human plasma using an immunoaffinity chromatographic extraction procedure and sensitive RIA. Immunoreactive CRH was detectable in the plasma of all normal subjects (mean +/- SD, 6.2 +/- 2.4 pg/mL; n = 15). Basal (0800-1000 h) plasma immunoreactive CRH levels were significantly lower in patients with Cushing's syndrome due to adrenal (2.8 +/- 1.1 pg/mL; n = 4) or pituitary adenomas (2.9 +/- 0.8 pg/mL; n = 5), in patients with hypothalamic hypopituitarism (3.2 +/- 0.9 pg/mL; n = 5), and in glucocorticoid-treated patients (3.9 +/- 1.9 pg/mL, n = 8). Basal plasma CRH levels were also low in patients with acromegaly (2.8 +/- 0.8 pg/mL; n = 14) and insulin-treated diabetic patients whose pituitary-adrenal function was normal (3.6 +/- 1.0 pg/mL; n = 12). In normal subjects plasma CRH levels increased after insulin-induced hypoglycemia; this response was abolished by the prior administration of dexamethasone. In contrast, basal plasma CRH levels were not affected by prior administration of metyrapone or dexamethasone. No evidence for diurnal variation in plasma immunoreactive CRH was found in normal subjects. In addition, in normal subjects oral glucose administration elicited a significant increase in plasma CRH (basal, 7.3 +/- 0.9 pg/mL; peak 30 min after glucose, 16.7 +/- 5.8 pg/mL; n = 5; P less than 0.05) without concomitant changes in ACTH. Gel filtration of extracts of pooled plasma from normal subjects revealed a major component of immunoreactive CRH in the position of synthetic rat CRH. Immunoreactive CRH-sized material had the same retention time as authentic rat CRH in a reverse phase high pressure liquid chromatography system. The content of immunoreactive CRH in human placenta, pancreas, and adrenal gland was much larger than that in hypothalamus. These findings suggest that immunoreactive CRH is present in peripheral plasma; the increase in plasma immunoreactive CRH after insulin-induced hypoglycemia may reflect stimulation of hypothalamic CRH release; the increase in plasma immunoreactive CRH after glucose administration may reflect extrahypothalamic CRH release; and the lack of diurnal variation in plasma immunoreactive CRH together with the lack of suppression of CRH by dexamethasone suggest that basal plasma CRH is of extrahypothalamic origin.

Objective: The role of endogenous GHRH in arginine-, insulin-, clonidine-and L-dopa-induced GH secretion was studied in man using a GHRH antagonist (GHRH-Ant). Design: Ten healthy adult males were studied for serum GH responses to arginine or insulin singly, or sequentially 120 min after GHRH injection with or without combined administration of GHRH-Ant. Further, GHRH, clonidine or L-dopa were sequentially administered to these subjects 120 min after the GHRH injection. Results: The combined administration of GHRH-Ant distinctly inhibited the arginine-and insulininduced GH release. When these four agents were sequentially administered 120 min after GHRH injection, the GH responses to clonidine and L-dopa disappeared completely while clear responses were observed to arginine and insulin administration. These responses to arginine and insulin were also completely inhibited by the combined administration of GHRH-Ant. Conclusions: These results indicate that clonidine and L-dopa stimulate GH secretion mainly through the release of hypothalamic GHRH, and that arginine-and insulin-induced hypoglycaemia stimulate GH secretion mainly through the inhibition of hypothalamic somatostatin release. However, the presence of endogenous hypothalamic GHRH seems to be essential for the maximal stimulation of GH release induced by arginine and insulin.