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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of estradiol on the brain concentration of immunoreactive beta-endorphin (beta-EP) and C-terminal ACTH (CLIP) was studied in ovariectomized rats. Dopamine, a known inhibitor of pituitary intermediate lobe pro-opiomelanocortin (POMC), was examined as a possible mediator of the estradiol induced changes in brain POMC. Animals were treated for 1 or 3 weeks with either 1) saline; 2) silastic estradiol implants; or 3) estradiol implants plus haloperidol 1 mg/kg/day. After one week of treatment no significant change in hypothalamic beta-EP content was noted in any group compared to the control level of 4.13 +/- .33 (SEM) pmoles although in the neurointermediate lobe beta-EP increased from 566 +/- 72 to 942 +/- 73 pmoles after haloperidol (p less than .005). After 3 weeks, however, hypothalamic beta-EP decreased from 3.96 +/- .28 to 2.74 +/- .19 pmoles (p less than .005) and C-terminal ACTH decreased from 3.78 +/- .33 to 2.82 +/- .18 pmoles (p less than .02) in the estradiol treated rats. This estradiol induced decrease in the hypothalamic content of beta-EP and C-terminal ACTH was not blocked by haloperidol. We conclude that estradiol lowers the hypothalamic content of beta-EP and CLIP and that this effect does not appear to be mediated by dopamine.
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PMID:Regulation of beta-endorphin and ACTH in brain by estradiol. 299 73

Human insulin (BHI, recombinant DNA) and pork insulin (PI) were compared in 10 healthy volunteers. Using a glucose controlled insulin infusion system for the performance of the insulin hypoglycemia test (IHT), a comparable dosage of both insulins had to be infused (BHI 0.129 +/- 0.007 vs PI 0.115 +/- 0.01 U/kg; mean +/- SEM). Blood glucose slopes and nadirs did not differ significantly (BHI 30 +/- 2 vs PI 29 +/- 2 mg/dl). There was no difference in C-peptide inhibition (minimum for BHI 0.50 +/- 0.08 vs PI 0.42 +/- 0.08 micrograms/l). Maximum hormone responses were identical for ACTH (BHI 78.4 +/- 11.3 vs PI 76.0 +/- 8.7 pg/ml), cortisol (BHI 246 +/- 20 vs PI 252 +/- 15 ng/ml) and GH (BHI 43.8 +/- 7.3 vs PI 49.4 +/- 6.7 ng/ml). Peak levels of prolactin did not differ significantly (BHI 1,335 +/- 315 vs PI 1,766 +/- 614 microU/ml). The urinary excretion pattern of epinephrine in three 120 min periods before, during and after IHT was identical (before IHT: BHI 0.9 +/- 0.2 vs PI 0.6 +/- 0.1 micrograms/120 min; during IHT: BHI 12.6 +/- 2.2 vs PI 13.4 +/- 2.5 micrograms/120 min; after IHT: BHI 2.5 +/- 0.7 vs PI 3.7 +/- 1.3 micrograms/120 min). No differences in the minima of serum potassium levels were observed (BHI 3.38 +/- 0.04 vs PI 3.33 +/- 0.05 mmol/l). We conclude that the biological effects of human insulin and pork insulin are comparable. Our data do not support the assumption of a different hypothalamic handling of human insulin (recombinant DNA) and porcine insulin.
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PMID:Comparative study of hormonal counter-regulation during GCIIS-guided insulin hypoglycemia tests using human insulin (recombinant DNA) and pork insulin. 299 78

Hyperprolactinemic patients may have increases in plasma dehydroepiandrosterone (DHA) and dehydroepiandrosterone sulfate (DHAS). We examined the effect of lowering serum PRL with bromocriptine or pituitary surgery on the serum concentrations of adrenal androgens and on the production rate (PR) and MCR of DHAS in eight hyperprolactinemic women (HP). We also examined the effect of bromocriptine therapy on adrenal androgens in five normal men. Serum DHAS was elevated in HP compared to normal women (mean +/- SEM, 254 +/- 28 vs. 182 +/- 13 microgram/dl; P less than 0.04). Serum DHA and androstenedione (delta 4) in HP were not significantly different from normal. Serum PRL fell from 160 +/- 16 to 37 +/- 9 ng/ml during or after treatment. Mean 24-h serum DHAS fell from 198 +/- 30 to 106 +/- 17 micrograms/dl (P less than 0.001) with treatment, without a change in the mean 24-h serum cortisol concentration (6.2 +/- 0.4 vs. 6.6 +/- 0.4 micrograms/dl). Thus, the DHAS to cortisol (DHAS/F) ratio fell significantly (32 +/- 5 to 17 +/- 4; P less than 0.001). This was also true of the DHAS/F ratio during ACTH stimulation (8 +/- 1 to 6 +/- 1; P less than 0.02). Similar changes were found in basal and ACTH-stimulated DHA/F ratios, whereas the basal and ACTH-stimulated delta 4/F ratios did not change significantly with treatment. Treatment lowered the PR of DHAS from 27 +/- 5 to 17 +/- 3 mg/24 h (P less than 0.03) and increased the DHAS MCR from 16 +/- 2 to 21 +/- 3 liters/24 h (P less than 0.01). Bromocriptine treatment of normal men lowered serum PRL from 15 +/- 2 to less than 2.5 ng/ml. There were no significant changes in the basal and ACTH-stimulated serum DHAS/F, DHA/F, or delta 4/F ratios or DHAS PR and MCR during bromocriptine therapy. The failure of bromocriptine to significantly alter these steroids in normal men suggests that bromocriptine was not directly responsible for the changes in HP treated with this drug. A mechanism for the increased PR of DHAS in HP was sought by examining the serum concentrations of the steroid biosynthetic intermediates relevant to DHAS production. Lowering serum PRL was associated with a decrease in basal and ACTH-stimulated 17-hydroxypregnenolone/17-hydroxyprogesterone and DHA/delta 4 ratios, suggesting an increase in 3 beta-hydroxysteroid dehydrogenase/delta 4,5-isomerase activity. However, increased gonadal secretion of the delta 4-steroids may have occurred with the fall in serum PRL.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The effect of serum prolactin on plasma adrenal androgens and the production and metabolic clearance rate of dehydroepiandrosterone sulfate in normal and hyperprolactinemic subjects. 299 77

The rise in cortisol in fetal sheep during late pregnancy has been related to increased responsiveness of the adrenal to ACTH. Most reports have suggested that plasma ACTH concentrations rise coincident with or after the prepartum increase in cortisol. To reexamine the relationship of cortisol with basal immunoreactive ACTH (IR-ACTH) throughout the last 40 days of pregnancy and to determine changes in fetal pituitary responsiveness during this time, we measured basal and synthetic ovine corticotrophin-releasing factor (oCRF) (10 ng-10 micrograms) induced rises in ACTH and cortisol in fetal sheep at days 110-115, 125-130, and 135-140 of pregnancy. The fetuses were catheterized on day 105-120 and entered spontaneous labour at greater than 140 days. Basal IR-ACTH (picograms per millilitre +/- SEM) rose from 16.7 +/- 2.9 pg/mL at day 110-115 to 34.8 +/- 8.7 pg/mL at day 141-145. There was a significant effect of time on basal ACTH concentrations with a mean increase of approximately 5 pg ACTH per millilitre of plasma per 5-day sampling interval. Plasma cortisol changed gradually between day 110 and 125 of gestation and then more rapidly to term. At day 110-115 of gestation there was no significant change in plasma ACTH after 10 or 100 ng oCRF, but there was a significant increase in ACTH after 1 microgram of oCRF. Plasma cortisol did not change after any CRF injection. The change in IR-ACTH after oCRF at day 125-130 of gestation was significantly greater than that at day 110-115. Plasma cortisol concentrations were elevated following 1- and 10-micrograms injections of oCRF.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Changes in pituitary responses to synthetic ovine corticotrophin releasing factor in fetal sheep. 300 May 58

We have determined metabolic parameters for androstenedione (A) in chronically catheterized late gestation (day 130) sheep fetuses. The MCR (MCRA) was 3210 +/- 229 (SEM, n = 12) ml/min, the fetal arterial whole blood concentration of A [A] was 65 +/- 5 pg/ml, and the blood production rate (PRA) was 204 +/- 20 ng/min. Pulsatile administration of ACTH in amounts that raised fetal arterial plasma cortisol concentrations by 5- to 7-fold increased [A] to 154 +/- 20 pg/ml and PRA to 471 +/- 31 ng/min with no change in MCRA. In the presence of metopirone to block fetal adrenal cortisol output, ACTH treatment still provoked elevations in [A] (to 198 +/- 23 pg/ml) and PRA (539 +/- 158 ng/min), without altering MCRA. The major radiolabeled product in blood of infused [3H]A was [3H]testosterone; smaller amounts of phenolic steroids were formed. Extensive metabolism of [3H]A occurred in whole blood in vitro. The major product was [3H]testosterone; the 17-oxidoreductase activity was associated with the red blood cells. Umbilical vein [A] was greater than umbilical artery [A]; ACTH treatment increased [A] in both vessels. Concomitant metopirone abolished the arteriovenous difference by eliminating the ACTH-induced increase in venous [A], although arterial [A] rose significantly. The venous [A] and the arteriovenous gradient were restored with exogenous glucocorticoid treatment to the fetus. Collagenase-dispersed fetal adrenal cells secreted A. Adrenal cells from fetuses pretreated with ACTH in vivo had higher basal and ACTH-induced output of A in vitro than cells from fetuses pretreated with saline in vivo. We conclude that the MCRA in fetal sheep is extremely high, in part due to conversion of A to testosterone in fetal blood. The elevated PRA after ACTH plus metopirone and the lack of an umbilical arteriovenous gradient of [A] in this, but not other groups of fetuses, suggests a source of A production independent of the cortisol-induced changes in the placenta. Direct evidence is provided for fetal adrenal secretion of A which is enhanced by ACTH pretreatment of the fetus in vivo and for the utilization of circulating A in the fetus as a precursor for estrogen in both fetal and maternal compartments.
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PMID:Androstenedione metabolism in the late gestation sheep fetus. 300 Jul 49

Pituitary-adrenocortical responses to the iv injection of 100 micrograms synthetic ovine corticotropin-releasing hormone (CRH) were studied in 13 patients with anorexia nervosa, and the concentrations of immunoreactive CRH in cerebrospinal fluid were measured in 7 of them. Mean basal levels of plasma ACTH and cortisol were 32 +/- 5 pg/ml (+/- SEM) and 21.1 +/- 1.5 micrograms/dl, respectively. The latter value was significantly higher than that in age-matched normal women (P less than 0.005). The mean increments of plasma ACTH and cortisol in response to CRH injection in those 13 patients were 21 +/- 5 pg/ml and 5.3 +/- 1.7 micrograms/dl, respectively, significantly lower than those in normal women (58 +/- 6 pg/ml and 15.3 +/- 7.7 micrograms/dl, respectively; P less than 0.005). When 4 patients were reexamined after weight gains of between 3 and 22 kg, their responses to the CRH injection increased. The mean concentration of immunoreactive CRH in the cerebrospinal fluid of seven patients was 30.8 +/- 3.9 pg/ml (+/- SEM), which was higher than the value of 18.4 +/- 1.1 pg/ml (P less than 0.005) in control subjects with cervical spondylosis. These findings suggest the possibility that hypersecretion of CRH may occur in patients with anorexia nervosa.
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PMID:The responses of plasma adrenocorticotropin and cortisol to corticotropin-releasing hormone (CRH) and cerebrospinal fluid immunoreactive CRH in anorexia nervosa patients. 300 Nov 25

SEM was used to visualize the normal postnatal development of the neonatal rat neuromuscular junction (nmj). Maturational changes evoked by ACTH/MSH 4-10 (10 micrograms/kg/day IP) or ACTH/MSH 4-9 (Org 2766) (0.01 microgram/kg/day IP) were compared to controls and to pups treated with nicotine during prenatal and postnatal life, or only during the gestation period. Pregnant females received 0.25 mg/kg 2X daily IP; neonates 0.05 mg/kg/day SC. The Desaki and Uehara and Fahim et al. methods revealed the nmj on the extensor digitorum muscle to be covered by a delicate drapery of postjunctional folds that surround the immature endplate region. By the second week of postnatal life, these folds become more complex and cover a larger area. Upon maturation the folds descend and invaginate into the muscle fiber. Peptide treatment with either ACTH/MSH 4-10 or ACTH/MSH 4-9 accelerates maturation of the endplate as demonstrated by the increased convolutions of the folds. Similar effects follow nicotine administration. The observed changes in morphology of the developing nmj subjected to nicotine may be mediated through nicotine-evoked ACTH release.
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PMID:ACTH peptides as organizers of neuronal patterns in development: maturation of the rat neuromuscular junction as seen by scanning electron microscopy. 300 72

Omeprazole, a substituted benzimidazole, is a potent inhibitor of gastric acid secretion which is currently being evaluated in patients with peptic ulcer and Zollinger-Ellison syndrome. Drugs which possess an imidazole nucleus have previously been shown to inhibit cortisol release from the adrenal cortex, secondary to inhibition of mitochondrial cytochrome P-450 dependent hydroxylation reactions. In a double-blind placebo-controlled crossover study in healthy male volunteers, omeprazole (60 mg daily for 7 days) did not alter basal cortisol levels. The peak cortisol response to ACTH stimulation was significantly reduced. Cortisol levels 60 min after ACTH were 824 +/- 27 nmol/l on omeprazole (mean +/- SEM), and 929 +/- 35 on placebo (P less than 0.005). In vitro, omeprazole caused a concentration-dependent inhibition of ACTH-stimulated cortisol release from isolated bovine adrenal cells (ED50 = 20 micrograms/ml). This was associated with a decrease in deoxycortisol synthesis. Therefore, unlike some other imidazole-containing drugs, the inhibitory effects of omeprazole are not entirely due to steroid 11 beta-hydroxylase inhibition. Substantial inhibition occurred at omeprazole concentrations which are higher than plasma levels normally achieved in clinical use. However, impairment of adrenocortical function may occur in patients on long-term high dose omeprazole treatment for Zollinger-Ellison syndrome.
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PMID:Inhibition by omeprazole of adrenocortical response to ACTH: clinical studies and experiments on bovine adrenal cortex in vitro. 300 7

The effect of conditioned vs. fresh culture medium on the dopaminergic inhibition of TSH and PRL secretion by primary cultures of male rat anterior pituitary cells has been studied. In the presence of conditioned medium (that had been in contact with the cells over the 3-day culture period) 10(-6) M dopamine (DA) inhibited PRL secretion by 50% and TSH secretion by 30%. After 4 h of incubation with fresh medium 10(-6) M DA still inhibited PRL secretion by 50% but increased TSH release by 20%. TSH release was rapid and could be prevented by 10(-6) M prazosin, an alpha 1 adrenoreceptor antagonist. Fresh medium did not alter TRH induced TSH release. In parallel cultures and under identical conditions fresh medium reduced [3H]dihydroergocryptine (DHE) binding to DA receptors from 2.5 +/- 0.4 fmol/10(5) cells to 0.95 +/- 0.3 fmol/10(5) cells (means +/- SEM, n = 5, P less than 0.001). The effect of fresh medium was dose dependent against the dopaminergic inhibition of TSH secretion and against DA receptor binding. If 1 mU TSH was included, in fresh medium, the dopaminergic inhibition of TSH secretion remained unchanged and [3H]DHE binding to DA receptors did not fall. The rank order of potency of thyroid stimulators was bovine TSH (21 U/mg) greater than semipurified bovine TSH (Thytropar, 1.4 U/mg) greater than endogenous rat TSH (0.03 U/mg expressed as NIADDK-rat TSH-RP2) greater than Graves' immunoglobulin G (0.01 U/mg) when either DA or bromocriptine was used as the dopaminergic agonist. When anterior pituitary cells from hypothyroid rats were examined, the effects of culture medium on the dopaminergic inhibition of TSH and on DA receptor binding were approximately twice those observed in normal cells, but the inclusion of 1 mU TSH in the fresh medium completely prevented the loss of DA function and binding. PRL, human CG, ACTH, insulin, glucagon, and heat-inactivated TSH were unable to prevent the effect of medium replacement on dopaminergic inhibition of TSH and DA receptor binding. The data suggest a mechanism whereby TSH may control its own secretion via DA.
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PMID:Thyrotropin regulates thyrotroph responsiveness to dopamine in vitro. 300 10

This study was designed to compare the responsiveness of adrenocorticotropin (ACTH) and cortisol secretion to corticotropin-releasing factor (CRF) in the morning and early evening in normal human subjects. Synthetic ovine CRF (1.0 micrograms/kg) or normal saline, was administered as an i.v. bolus injection to six normal males at 900 h and 1700 h. Blood samples were obtained before and 15, 30, 60, 90 and 120 min after CRF or saline injection. Significant increases in plasma ACTH and cortisol levels were observed in all subjects at the both time of testing after CRF injection. The net increments in the areas under the concentration curve (areas in the CRF experiment minus those in the saline control experiment) were not statistically different for both ACTH (mean +/- SEM: 41.0 +/- 10.6 pg/ml h in the morning: 51.1 +/- 8.9 pg/ml h in the evening) and cortisol (mean +/- SEM: 28.5 +/- 5.0 micrograms/dl h in the morning; 36.2 +/- 4.0 micrograms/dl h in the evening). Also no significant difference was observed in net increment, peak level and the ratio of peak level to the basal level of ACTH and cortisol after CRF injection. There were no appreciable changes in plasma concentrations of growth hormone, thyroid-stimulating hormone or prolactin, although slight but statistically significant rises in plasma levels of luteinizing hormone and follicle-stimulating hormone were observed. These results suggest that there is no significant difference in responsiveness of the pituitary-adrenal axis to CRF in the morning (900 h) and early evening (1700 h), and thus the time of day will not necessarily have to be considered when CRF is used between these times in a clinical test to evaluate pituitary ACTH reserve.
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PMID:Responses of plasma adrenocorticotropin and cortisol to intravenous injection of synthetic ovine corticotropin releasing factor in the morning and early evening in normal human subjects. 300 29


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