Human corticotropin-releasing factor plus lysine vasopressin test during glucocorticoid therapy.

1.0 micrograms/kg body wt human corticotropin-releasing factor (hCRF) and 0.005 IU/kg body wt lysine vasopressin (LVP) were administered in a bolus dose to patients receiving daily or alternate-day glucocorticoid therapy. In normal subjects with this hCRF-LVP test, the plasma ACTH increment was significantly greater (approximately 2.5-fold) 15 min after injection than under the CRF test. In patients receiving daily glucocorticoid therapy (greater than 15 mg prednisolone or an equivalent daily dose), the plasma ACTH and cortisol responses to hCRF-LVP were suppressed 2 wk to 1 mo after the beginning of glucocorticoid administration but partially improved at 2-10 mo, and was markedly suppressed several years later. On the other hand, in patients receiving alternate-day glucocorticoid therapy, the plasma ACTH response was normal at 2 wk, normal or higher at 1-3 mo, and normal after 4 mo. A normal plasma cortisol response was observed throughout the test period in patients receiving alternate-day therapy after pulse therapy, whereas plasma cortisol response was gradually improved in patients receiving alternate-day therapy after several months of daily therapy.

IDDM accompanied by a growth hormone-producing pituitary adenoma. A case report.

CASE HISTORY: A 30-year-old Japanese man who presented with recurrent ketoacidosis caused by IDDM was found to have increased secretion of growth hormone (GH). On initial cranial magnetic resonance imaging (MRI), no pituitary lesion was detected; however, a pituitary microadenoma was found 2 years later during a repeat MRI. In spite of the hypersecretion of GH, serum IGF-I was dramatically suppressed. Transsphenoidal surgery was performed to resect the pituitary tumor that was histologically an acidophilic pituitary adenoma. Although the GH excess rapidly improved postoperatively, the IGF-I level remained low. Subsequent insulin therapy initiated 1 year after the operation elevated the serum IGF-I level to within the normal range. DISCUSSION: The first case of coexistent IDDM and a GH-producing pituitary adenoma suggests that patients with uncontrolled IDDM may develop GH hypersecretion. Furthermore, the low IGF-I levels may be closely associated with the GH excess and with the development or progression of GH-secreting pituitary adenomas.

Concomitant increases in serum growth hormone and hypothalamic somatostatin in rats after injection of gamma-aminobutyric acid, aminooxyacetic acid, or gamma-hydroxybutyric acid.

gamma-Aminobutyric acid (GABA; 50 or 500 microgram/10 microliter) was injected into the right lateral ventricle of urethane- or pentobarbital-anesthetized male rats. The animals were decapitated 15 min after injection. Serum GH and hypothalamic somatostatin (SRIF) concentration were measured by specific RIAs. Intraventricular GABA caused a dose-related increase in GH and SRIF. In another study, aminooxyacetic acid (5 or 20 mg) was injected ip into urethane-anesthetized rats. Aminooxyacetic acid at 20 mg produced a significant increase in both serum GH and hypothalamic SRIF. Furthermore, 12.5 mg gamma-hydroxybutyric acid (GHB) injected ip into urethane- or pentobarbital-anesthetized rats elicited a significant increase in both serum GH and hypothalamic SRIF. Pretreatment with 20 mg L-dopa produced decreases in the GHB-induced serum GH increase and in hypothalamic SRIF in pentobarbital-anesthetized rats. These results show that GABA and GHB stimulated GH secretion, which was accompanied by increased hypothalamic SRIF. Thus, the GH release induced by GABA or GHB may be partly involved in inhibiting the release of hypothalamic SRIF. As the GHB-induced GH release was inhibited by L-dopa, the stimulatory effect of GHB on GH secretion might be mediated by inhibition of the dopaminergic mechanism.

Dual effects of (D-Ala2,Met5)-enkephalinamide on CRF and ACTH secretion.

An intra-third ventricular administration of (D-Ala2,Met5)-enkephalinamide (DALA) did not elevate plasma ACTH and corticosterone levels in unanesthetized freely moving rats, but intra-third ventricular administration of DALA and methionine (Met)-enkephalin potentiated a mild stress (hanging for 10 or 30 sec)-induced plasma ACTH and corticosterone elevations in unanesthetized freely moving rats. DALA and Met-enkephalin seemed to stimulate CRF release from the median eminence to increase plasma ACTH, as the CRF concentration in the median eminence area was reduced after injection in these stressed rats. When hypothalamic tissues were perifused in vitro, DALA (1-100 ng/ml) reduced the release of CRF. These results suggest that the opiates seem to have a dual effect on the CRF-ACTH system depending on which action overrides the other.

Atrial natriuretic peptide does not affect corticotropin-releasing factor-, arginine vasopressin- and angiotensin II-induced adrenocorticotropic hormone release in vivo or in vitro.

The effect of synthetic atrial natriuretic peptide (ANP) was examined on the in vivo and in vitro release of ACTH. Intravenous ANP (4 micrograms/kg body weight) administration did not affect the corticotropin releasing factor (CRF, 4 micrograms/kg body weight)-, arginine vasopressin (AVP, 2 micrograms/kg body weight)- and angiotensin II (A II, 4 micrograms/kg body weight)-induced ACTH release in unanesthetized freely moving rats. ANP did not inhibit the basal, CRF- and AVP-induced release of ACTH in pituitary cell cultures. ANP did not affect the CRF- and AVP-induced plasma corticosterone elevation, while it attenuated the AVP-induced corticosterone elevation. These results indicate that ANP does not affect the ACTH release at the pituitary level in vivo and in vitro.

Long-term administration of adrenocorticotropin modulates the expression of IGF-I and TGF-beta 1 mRNAs in the rat adrenal cortex.

The effects of long-term adrenocorticotropin (ACTH) therapy on the expression of IGF-I and TGF-beta 1 on rat adrenal cortex was investigated. ACTH (0.1 mg/kg/day) or saline as control was injected intraperitoneally in 5-week-old Wistar rats every day for 4 weeks. ACTH significantly increased adrenal weight (P < 0.05) and serum corticosterone (P < 0.05). Competitive RT-PCR analysis on the adrenocortical mRNA showed increased IGF-I (P < 0.01) at 4 weeks of ACTH and increased TGF-beta 1 (P < 0.01) at 1 week of ACTH compared the control group. ACTH also significantly increased proliferating cell nuclear antigen mRNA level (P < 0.01), at 4 weeks of treatment, which correlated with IGF-I level (P < 0.01), but correlated negatively with ACTH-stimulated TGF-beta 1 level (P < 0.05). There was a weak correlation between IGF-I and serum corticosterone (P < 0.05), and between TGF-beta 1 mRNA levels and serum corticosterone concentration (P < 0.05). Histologically, ACTH induced hypertrophy in the zona fasciculata cells and increased the clear cells containing lipid deposits. Immunohistochemistry showed that IGF-I peptide was mainly expressed in the periphery of the zona fasciculata at 4 weeks of ACTH therapy, while the same therapy caused a slight increase in TGF-beta 1 expression in the same area. Our results show that an increase in adrenocortical growth resulting from ACTH treatment is associated with an increase in IGF-I mRNA expression but only a transient increase in TGF-beta 1 mRNA expression.

The magnocellular arginine-vasopressin mRNA responds differently to food deprivation between the supraoptic and paraventricular nuclei of the hypothalamus in adrenalectomized rats with low corticosterone replacement.

We previously reported that food deprivation significantly decreased arginine-vasopressin (AVP) mRNA levels in the supraoptic (SON) and paraventricular (PVN) nuclei of the hypothalamus and also greatly stimulated the pituitary-adrenocortical system in rats. In this study, we deprived adrenalectomized rats with subcutaneously implanted low-dose corticosterone pellets (ADX + B) of food for 3 days to investigate the involvement of corticosteroid feedback regulation in the food deprivation-induced decrease in AVP mRNA in both the SON and the PVN. The plasma corticosterone levels in these animals were maintained at low levels constantly over 24 h. The ACTH concentration in the morning plasma was markedly increased in the food-deprived ADX + B rats as compared to the fed ADX + B rats. Food deprivation significantly decreased the corticotropin-releasing hormone (CRH) content in the median eminence and increased the CRH and AVP content in the neurointermediate lobe of the pituitary. Semiquantitative in situ hybridization histochemistry revealed that AVP mRNA levels were decreased in the SON but, inversely, increased in magnocellular as well as parvocellular subdivisions of the PVN following food deprivation. These results suggest that: (1) AVP mRNA responds differently to food deprivation between the SON and the PVN; (2) the glucocorticoid feedback can exert on AVP mRNA in the PVN but not in the SON in the food-deprived rats; and (3) food deprivation affects the neurohypophysial levels of CRH and AVP.

Central interaction between endothelin and brain natriuretic peptide on pressor and hormonal responses.

Interaction between intracerebroventricular (i.c.v.) administration of endothelin (ET) and brain natriuretic peptide (BNP) on pressor and hormonal responses was examined in unanesthetized, freely moving rats. I.c.v. administered ET (5, 20 or 40 pmol/2 microliters) dose-dependently increased arterial pressure. Plasma catecholamine levels were elevated by 40 pmol of ET, and plasma ACTH level was also elevated by centrally administered ET in a dose-dependent manner. I.c.v. administration of BNP (0.2, 1 nmol/3 microliters) dose-dependently attenuated central ET (40 pmol/2 microliter)-induced pressor response, plasma catecholamine and ACTH secretion. These results indicate that ET may be one of the neuropeptides which stimulate both sympathetic nervous system and hypothalamo-pituitary-adrenal axis, and that BNP and ET interact in the central nervous system (CNS) to regulate cardiovascular and hormonal functions. Furthermore, these results raise a possibility that BNP antagonizes the effect of not only angiotensin II but also other neuropeptides in the CNS.

Starvation-induced changes in rat brain corticotropin-releasing factor (CRF) and pituitary-adrenocortical response.

Starvation-induced changes in CRF concentration in major brain regions and abnormalities in the pituitary-adrenal axis were examined in rats using rat CRF radioimmunoassay. The CRF concentrations in the hypothalamus and cerebellum were significantly reduced in the completely starved rats, while those in the midbrain, thalamus and neurointermediate lobe of the pituitary were significantly increased in the semi-starved or completely starved rats. No significant changes in the CRF concentrations were found in the pons, medulla oblongata and cerebral cortex. In the completely starved rats, the serum ACTH level was significantly reduced, whereas the serum corticosterone level was markedly elevated. These observations suggest that starvation may stimulate the CRF-ACTH-corticosterone system and that not only hypothalamic CRF but also extrahypothalamic CRF may be discretely related to feeding behavior or starvation. The reduced serum ACTH level in starved rats may be ascribed to the negative feedback effect of the elevated serum corticosterone.

Reduction in brain immunoreactive corticotropin-releasing factor (CRF) in spontaneously hypertensive rats.

The brain CRF concentration of spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY) was examined by rat CRF radioimmunoassay. Anti-CRF serum was developed by immunizing rabbits with synthetic rat CRF. Synthetic rat CRF was also used as tracer and standard. The displacement of 125I-rat CRF by serially diluted extracts of male Wistar rats hypothalamus, thalamus, midbrain, pons, medulla oblongata, cerebral cortex, cerebellum and neurointermediate lobe was parallel to the displacement of synthetic rat CRF. In both WKY and SHR the highest levels of CRF immunoreactivity were shown by the hypothalamus and neuro-intermediate lobe, and considerable CRF immunoreactivity was also detected in other brain regions. The CRF immunoreactivity in the hypothalamus, neurointermediate lobe, midbrain, medulla oblongata and cerebral cortex was significantly reduced in SHR and it may suggest that CRF abnormality may be implicated in the reported abnormalities in the pituitary-adrenal axis, autonomic response and behavior of SHR.

Cerebrospinal fluid and plasma corticotropin-releasing hormone in senile dementia.

Cerebrospinal fluid (CSF) levels of corticotropin-releasing hormone (CRH) and ACTH, and plasma levels of CRH, ACTH and cortisol were determined in samples taken simultaneously from 28 patients with dementia including senile dementia of the Alzheimer type (SDAT), multi-infarct dementia (MID), dementia following a cerebrovascular accident (CVD), and the borderline-to-normal state. CRH levels in CSF were significantly reduced in patients with SDAT and CVD, but not in those with MID, as compared with the borderline cases. ACTH levels in CSF were significantly reduced in the patients with SDAT compared to those with MID. Reduced CRH levels in CSF were found in the patients who showed severe dementia and poor activities of daily living (ADL). Plasma levels of CRH, ACTH and cortisol were normal and were not significantly different among the four groups of patients. CRH levels in CSF were positively correlated with ACTH levels in CSF, but not with the levels of plasma CRH, ACTH or cortisol. Plasma CRH levels were positively correlated with plasma ACTH levels. These results suggest that: 1) abnormalities in the extrahypothalamic CRH system play a role in the pathophysiology of senile dementia, which may not be specific to SDAT; 2) CSF CRH is correlated with the severity of dementia and ADL; 3) the levels of CRH in CSF and plasma are independent, and 4) the plasma CRH reflects, at least in part, the activity of the hypothalamic CRH regulating the secretion of pituitary ACTH.

Renal c-fos expression induced by angiotensin II is enhanced in spontaneously hypertensive rats.

We compared the effect of a bolus injection of angiotensin II (Ang II) on the expression of protooncogene c-fos in the renal cortex and medulla of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. Intravenous infusion of 5 ng/kg body weight of Ang II resulted in an immediate rise in systolic blood pressure (SBP) in both SHR and WKY rats. The percent rise in SBP was similar in both strains. Pretreatment with Ang II type 1 (AT1)-receptor antagonist, L-158,809 (1 mg/kg) abolished the pressor response in both strains. Competitive reverse transcription-polymerase chain reaction (RT-PCR) showed that administration of Ang II increased the expression of c-fos mRNA within 10 min in both the renal cortex and medulla of SHR significantly higher than WKY rats. Moreover, the enhanced c-fos mRNA expression due to Ang II was significantly suppressed by the pretreatment of L-158,809 in both strains. These findings indicate that c-fos expression in the kidney is mediated by AT1-receptors and that the renal c-fos response to exogenous Ang II was significantly augmented in SHR compared with WKY rats, suggesting that this hyperresponsiveness on renal AT1-action may partly contribute to the progression of renal injury in SHR.

Cerebrospinal fluid corticotropin-releasing hormone and ACTH, and peripherally circulating choline-containing phospholipid in senile dementia.

Cerebrospinal fluid (CSF) levels of corticotropin-releasing hormone (CRH) and ACTH, plasma levels of ACTH and cortisol, and serum levels of phospholipid and its fractions were determined in samples taken simultaneously from patients with senile dementia of the Alzheimer type (SDAT), multi-infarct dementia (MID) or dementia following a cerebrovascular accident (CVD), and the borderline-to-normal control subjects. CRH levels in CSF were significantly reduced in patients with SDAT and CVD but not with MID compared to the borderline-to-normal controls. ACTH levels in CSF were significantly reduced in SDAT compared to MID. The levels of circulating lecithin (phosphatidyl-choline) were depressed in a similar fashion to the levels of CRH in CSF in the SDAT patients and the group of severe dementia. Dementia and its severity did not affect the morning plasma levels of ACTH and cortisol. CSF CRH was positively correlated with CSF ACTH, while CSF ACTH was negatively correlated with plasma cortisol. No significant correlations were found between serum lecithin and CSF CRH or ACTH. These findings suggest that: 1) abnormalities in the extrahypothalamic CRH system play a role in the pathophysiology of senile dementia, which may not be specific to SDAT; 2) the CRH system and the ACTH system correlate with each other within the brain; 3) CSF ACTH is subject to the feedback inhibition by circulating cortisol; and 4) in the SDAT patients and the severe dementia group CSF CRH and serum lecithin are reduced probably via independent mechanisms.

A specific radioimmunoassay for corticotropin releasing factor (CRF) using synthetic ovine CRF.

This newly developed specific radioimmunoassay for corticotropin releasing factor (CRF) had a sensitivity range of 25 pg/tube to 4 ng/tube. Intra and interassay coefficient of variation were 4.6% and 9.8%, respectively. Rat median eminence extracts showed a parallel dose response curve with synthetic ovine CRF and a significant cross reaction was not evident with other tested neuropeptides. The highest mean levels of CRF were found in the median eminence (6.61 ng/mg protein). Considerable amounts of CRF were found in the arcuate nucleus, paraventricular nucleus, dorsomedial nucleus, suprachiasmatic nucleus and ventromedial nucleus. The immunoreactive CRF of the rat medial basal hypothalamus coeluted with bioassayable CRF and with iodinated CRF on Sephadex G-75 chromatography. The results indicate that rat hypothalamus contains a CRF similar to ovine CRF.

Crohn's disease associated with growth hormone secretory dysfunction.

A 10-year-old boy presented in 1989 with repeated episodes of vomiting, abdominal distension and severe growth retardation. Endocrinologic examination indicated growth hormone (GH) secretory dysfunction. Administration of recombinant human GH (rhGH) led to growth, but the patient discontinued treatment. He was readmitted to our hospital in 1993, at the age of 16. His stature was very short. Laboratory findings suggested malnutrition. Radiologic examination revealed regional stenosis and a cobblestone appearance of the intestine. The histologic diagnosis was compatible with Crohn's disease. Administration of prednisolone alleviated gastrointestinal symptoms with the improvement of GH secretory function.

A case of non-Hodgkin's lymphoma associated with hypercalcemia.

A patient with a diffuse, small cleaved cell, non-Hodgkin's lymphoma associated with marked hypecalcemia was described. Antibody to the adult T-cell leukemia-lymphoma virus was absent. Although bone marrow was infiltrated by lymphoma cells, destructive or lytic bone lesions could not be detected. The serum level of immunoreactive parathyroid hormone C-terminal (PTH-C) was normal. The serum level of 1, 25-dihydroxyvitamin D was lower than normal. This case suggests that other humoral substances produced by lymphoma cells may be responsible for hypercalcemia.

Combined anterior pituitary function test using CRH, GRH, LH-RH, TRH and vasopressin in patients with non-functioning pituitary tumors.

We examined 8 normal subjects and 16 patients with non-functioning pituitary tumors with a combined anterior pituitary test to evaluate the clinical usefulness of the test. Diagnoses included 9 of chromophobe adenoma, 3 of craniopharyngioma, 2 of Rathke's cleft cyst, and 1 each of intrasellar cyst and tuberculum sella meningioma. All subjects received hypothalamic releasing hormones: 1 micrograms/kg corticotropin releasing hormone (CRH), 1 micrograms/kg growth hormone releasing hormone (GRH), 500 micrograms thyrotropin-releasing hormone (TRH), 100 micrograms luteinizing hormone releasing hormone (LH-RH), and a relatively small dose (5 mU/kg) of lysine vasopressin (LVP). In the normal subjects, the addition of LVP potentiated the secretion of adenocorticotropic hormone (ACTH) induced by CRH, but had no significant effect on the secretion of other anterior pituitary hormones. In the combined test with 5 releasing hormones, the plasma ACTH and cortisol responses were not impaired in the majority of the patients before pituitary surgery. Serum thyroid-stimulating hormone (TSH), prolactin (PRL) and follicle-stimulating hormone (FSH) responses were not impaired in 82%, 70% and 67% of the patients, respectively, while the serum LH and GH responses were impaired in 67% and 73% of the patients, respectively. Following pituitary surgery, responses of these hormones to combined testing were similarly impaired in more than 75% of the patients. These results indicate that plasma ACTH, cortisol and serum TSH responses are fairly good before pituitary surgery but are impaired significantly after surgery. No subjects experienced any serious adverse effects related to the testing. These results suggest that combined testing with hypothalamic hormones is a convenient and useful method for evaluating pituitary function.

A different distribution of corticotropin releasing factor and arginine vasopressin contents in the hypothalamic nuclei after estrogen administration.

The distribution of corticotropin releasing factor (CRF) and arginine vasopressin (AVP) in hypothalamic nuclei were examined in control and estrogen-treated female rats. CRF activity was measured using monolayer cultured rat anterior pituitary cells and AVP by radioimmunoassay. Hypothalamic nuclei were punched out according to the method of Palkovits. The distribution of CRF activity in 5 different hypothalamic nuclei was similar to that of AVP in intact female rats. CRF activity in hypothalamic nuclei, pituitary ACTH content and plasma ACTH levels in estrogen-treated rats were not significantly different from those in control rats. However, significant elevation of AVP content was observed in the supraoptic and paraventricular nuclei of estrogen-treated rats. These results indicate that CRF and AVP are distributed in similar hypothalamic nuclei, but that they are not identical.

Enhanced pressor response in spontaneously hypertensive rats induced by stimulation of vasopressin-V1 receptors.

To elucidate the effect of the arginine vasopressin (AVP) system in vivo, especially V1 and V2 activity, on blood pressure, we measured the acute changes in blood pressure and heart rate after AVP, OPC-21,268 (a V1 receptor antagonist), and OPC-31,260 (a V2 receptor antagonist) were injected intravenously in anesthetized spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats at the age of 15 weeks. Compared with the control period, single injection of AVP 5 ng/kg significantly increased systolic blood pressure in WKY rats without a concomitant increase in heart rate, but there was no significant increase in blood pressure in SHR. In contrast, single injection of either OPC-21,268 3 mg/kg or OPC-31,260 3 mg/kg did not affect blood pressure or heart rate in either SHR or WKY rats. Injection of AVP after the administration of OPC-31,260 induced a greater increase in blood pressure in SHR than in WKY rats, whereas injection of AVP after the administration of OPC-21,268 did not induce any clear increase in blood pressure in SHR or WKY rats. These results suggest that SHR have enhanced pressor activity mediated by V1 receptors and that this increase may be due to an increase in their number. In conclusion, enhancement of V1 activity may contribute to the development of high blood pressure in SHR.

Pharmacologically stimulated portal flow measurement by magnetic resonance imaging for assessment of liver function.

PURPOSE: To evaluate pharmacologically stimulated portal flow measured by magnetic resonance (MR) imaging for assessment of liver function. MATERIALS AND METHODS: Pharmacologically stimulated portal flow was measured by phase contrast MR imaging in 27 patients when they were undergoing abdominal angiography for liver tumors or gall bladder cancer. The patients included 11 cases of liver cirrhosis and eight of chronic hepatitis. Pharmacological stimulation was done by infusion of 10 microg/Kg of nicardipine hydrochloride into the superior mesenteric artery through an angiographic catheter. We examined the correlation between stimulated or non-stimulated portal flow and biochemical liver function tests. RESULTS: Correlation coefficients and their corresponding p values between non-stimulated portal flow and the indocyanine green residual rate at 15 min after injection (ICG R15), serum albumin (ALB), total bilirubin (TB), cholinesterase (CHE), and hepaplastin test (HP) were--0.414 (0.056), 0.296 (0.134), -0.570 (0.002), 0.289 (0.153), and 0.321 (0.126), respectively, whereas those between stimulated portal flow and ICG R15, ALB, TB, CHE, and HP were--0.561 (0.007), 0.411 (0.033), -0.509 (0.007), 0.445 (0.023), and 0.494 (0.014), respectively. CONCLUSION: Stimulated portal flow showed better correlations with biochemical liver function tests than non-stimulated portal flow. It is suggested that stimulated portal flow measurement is more useful for the evaluation of liver function than non-stimulated portal flow measurement.