G. K. Stalla

Corticotropin releasing factor (CRF)-stimulation test in normal controls and patients with disturbances of the hypothalamo-pituitary-adrenal axis

SummaryIntravenous application of 100 µg synthetic ovine corticotropin releasing factor (CRF) led to stimulation of ACTH-secretion in nine normal controls, with a maximum 30 min after CRF. Cortisol, corticosterone, cortisone and 11-deoxycortisol increased with a maximum at 60 min after CRF, whereas no rise was seen in aldosterone, 11-deoxycorticosterone, 17-α-hydroxyprogesterone, progesterone, DHEA-S and testosterone. The specificity of CRF-stimulation was also shown by unchanged TSH, LH, FSH, hGH, prolactin and thyroid hormone levels, als well as unchanged insulin and gastrin levels. No serious side-effects were observed during the test period and afterwards.CRF-tests were performed in ten patients with disturbances of the hypothalamo pituitary adrenal axis (HPAA). Preliminary findings show hyperresponsiveness of ACTH in all situations of ACTH-hypersecretion (two patients with Cushings disease, one patient with Nelsons syndrome, and one with Addisons disease). In contrast, one patient with successful microadenomectomy showed no response of ACTH to CRF, whereas in another patient with a macroadenoma ACTH and cortisol-levels still increased postoperatively. Divergent patterns in ACTH-responsiveness to CRF were seen in four patients with secondary adrenal insufficiency, allowing the localization of the defect. These data point to the possible importance of the “CRF-test” as a differential diagnostic tool and prognostic factor in diseases of the HPAA.

Long-term remission and recurrence rates after first and second transsphenoidal surgery for Cushing's disease: care reality in the Munich Metropolitan Region

OBJECTIVE Transsphenoidal surgery (TSS) presents the treatment of choice for Cushings disease (CD). Remission and recurrence rates vary dependent on tumor size, extension, adenoma visibility on magnetic resonance imaging, and neurosurgical expertise. Other than published from single-surgeon neurosurgical series so far, we have aimed to describe long-term remission and recurrence rates of CD in a series incorporating different neurosurgeons, trying to reflect care reality in the Munich Metropolitan Region, which is accommodated by three tertiary university and multiple, smaller neurosurgical centers. DESIGN We conducted a retrospective analysis of 120 patients who underwent first and 36 patients who underwent second TSS as treatment for CD between 1990 and 2012. METHODS Patients were divided into three groups according to remission status. Potential risk factors for recurrence, pituitary function, and strategy in persistent disease were assessed. RESULTS THREE OUTCOME GROUPS WERE IDENTIFIED ACCORDING TO REMISSION STATUS AFTER FIRST TSS (MEAN FOLLOW-UP 79 MONTHS): remission, 71% (85/120), disease persistence, 29% (35/120), and disease recurrence, 34% (29/85) (mean time to recurrence 54 months). After second TSS (n=36, mean follow-up 62 months), we documented remission in 42% (15/36), disease persistence in 58% (21/36), and disease recurrence in 40% (6/15) (mean time to recurrence 42 months). Postoperative hypocortisolism after first, though not after second, TSS was associated with a lower risk of suffering disease recurrence (risk=0.72; 95% CI 0.60-0.88; exact significance (two-sided) P=0.035). CONCLUSIONS Our study shows higher recurrence rates of CD after first TSS than previously reported. Second TSS leads an additional 8% of the patients to long-term CD remission.

Human corticotropin-releasing hormone during pregnancy

Elevated irCRH levels up to 14 ng/ml were measured in 176 females in the last trimester. The highest maternal CRH levels were found in those females in whom the period from the onset of labour to full dilatation of the cervix and the time span of delivery were shortest. irCRH in amniotic fluid (120 +/- 180 pg/ml; n = 14) was in the same range as in umbilical cord plasma (233 +/- 188 pg/ml; n = 66) and 20-fold lower than in prepartal maternal plasma (5.38 +/- 4.49 ng/ml; n = 66). irCRH in maternal plasma correlated highly to irCRH in umbilical cord plasma (p less than 0.001; n = 66). After delivery irCRH disappeared from maternal plasma with a half-life of 50 minutes (n = 14). One day postpartum irCRH levels (n = 22) were undetectable. The height of the irCRH levels in the various biological fluids did not correlate to the mode or the pathological events of delivery (n = 43). Maternal ACTH levels above the normal range were encountered only in women immediately prepartal and did not correlate to the CRH levels (253 +/- 229 pg/ml; n = 66). Cortisol levels were higher in maternal plasma than in umbilical cord plasma due to elevated CBG (n = 78). Free cortisol levels were higher in the 3rd trimester than in the 1st (2.18 +/- 0.16 vs 1.16 +/- 0.73 ng/ml; n = 42). irCRH in maternal and umbilical cord plasma correlated to the hPl and estriol levels (p less than 0.001 and p less than 0.05; n = 66). We conclude that irCRH is secreted by the placenta into both maternal and fetal circulation. Though placental CRH is undistinguishable from hypothalamic CRH, the biological significance of placental CRH remains open. Our data show that placental CRH might be responsible for the changed function of the adrenal gland during pregnancy, with higher free cortisol levels in the last trimester. The extremely elevated ACTH levels during labour and delivery indicate that CRH is not the only mediator of stress-induced ACTH secretion in the regulation of the maternal hypothalamo-pituitary-adrenal axis.

Favorable long-term outcomes of bilateral adrenalectomy in Cushing's disease

OBJECTIVE Bilateral adrenalectomy (BADX) is an important treatment option for patients with Cushings syndrome (CS). Our aim is to analyze the long-term outcomes, surgical, biochemical, and clinical as well as morbidity and mortality, of patients who underwent BADX. DESIGN A total of 50 patients who underwent BADX since 1990 in two German centers were identified. Of them, 34 patients had Cushings disease (CD), nine ectopic CS (ECS), and seven ACTH-independent bilateral adrenal hyperplasia (BAH). METHODS Standardized follow-up examination was performed in 36 patients with a minimum follow-up time of 6 months after BADX and a median follow-up time of 11 years. RESULTS Surgical morbidity and mortality were 6 and 4% respectively. All patients were found to be in remission after BADX. Almost all Cushings-specific comorbidities except for psychiatric diseases improved significantly. Health-related quality of life remained impaired in 45.0% of female and 16.7% of male patients compared with a healthy population. The median number of adrenal crises per 100 patient-years was four. Nelson tumor occurred in 24% of CD patients after a median time span of 51 months. Long-term mortality after 10 years was high in ECS (44%) compared with CD (3%) and BAH (14%). CONCLUSIONS BADX is an effective and relatively safe treatment option especially in patients with CD. The majority of patients experience considerable improvement of Cushings symptoms.

A critical reappraisal of bilateral adrenalectomy for ACTH-dependent Cushing's syndrome

OBJECTIVE Our aim was to review short- and long-term outcomes of patients treated with bilateral adrenalectomy (BADx) in ACTH-dependent Cushings syndrome. METHODS We reviewed the literature and analysed our experience with 53 patients treated with BADx since 1990 in our institution. RESULTS BADx is considered if ACTH-dependent Cushings syndrome is refractory to other treatment modalities. In Cushings disease (CD), BADx is mainly used as an ultima ratio after transsphenoidal surgery and medical therapies have failed. In these cases, the time span between the first diagnosis of CD and treatment with BADx is relatively long (median 44 months). In ectopic Cushings syndrome, the time from diagnosis to BADx is shorter (median 2 months), and BADx is often performed as an emergency procedure because of life-threatening complications of severe hypercortisolism. In both situations, BADx is relatively safe (median surgical morbidity 15%; median surgical mortality 3%) and provides excellent control of hypercortisolism; Cushings-associated signs and symptoms are rapidly corrected, and co-morbidities are stabilised. In CD, the quality of life following BADx is rapidly improving, and long-term mortality is low. Specific long-term complications include the development of adrenal crisis and Nelsons syndrome. In ectopic Cushings syndrome, long-term mortality is high but is mostly dependent on the prognosis of the underlying malignant neuroendocrine tumour. CONCLUSION BADx is a relatively safe and highly effective treatment, and it provides adequate control of long-term co-morbidities associated with hypercortisolism.

Corticotropin-releasing factor (CRF): stimulation in normal controls and in patients with Cushing's syndrome.

Synthetic ovine and human CRF were given as an i.v. bolus to six healthy volunteers in four and two different dosages, respectively (oCRF: 25, 50, 100 and 200 micrograms; hCRF: 50 and 100 micrograms). There was a significant increase of ACTH and cortisol after the injection of all dosages though the dose-response relationship was only significant between the 50 and 100 micrograms dose of oCRF. No significant differences between ACTH and cortisol secretion after oCRF and hCRF were observed. Repetitive stimulation by hCRF led to repetitive release of identical amounts of ACTH. The CRF test with the 100 micrograms dosage was used in patients with proven Cushings syndrome (n = 30). Results showed that the CRF test is useful in making the differential diagnosis of established Cushings syndrome. In patients with ACTH-dependent Cushings disease (n = 21), normal or elevated basal ACTH levels were significantly higher after stimulation by CRF compared to normal controls, with one exception. The pattern of cortisol secretion after CRF administration corresponded to the pattern of ACTH secretion in these patients. In two patients with ectopic ACTH syndrome, extremely elevated ACTH and cortisol levels did not change or showed only a small increase after CRF administration. In patients with unilateral adrenal adenoma or carcinoma (n = 7), suppressed ACTH levels did not rise after CRF administration. In addition, no significant change in cortisol secretion could be observed. After surgical removal of cortisol-producing adrenal tumors, the ACTH response to CRF can be demonstrated when cortisol levels are still undetectable. Pulsatile administration of CRF in one patient after unilateral adrenalectomy revealed that ACTH responses to CRF normalize rapidly but cannot be sustained if CRF administration is withdrawn, suggesting that the cause of adrenal failure after unilateral adrenalectomy for Cushings syndrome or with long-term corticoid therapy is due to hypothalamic CRF deficiency. The suppression of ACTH responses to CRF in glucocorticoid-treated patients correlated with the daily corticoid dosage. Since the ACTH hyper-response to CRF in six patients with Cushings disease was suppressed by short-term dexamethasone treatment, the pituitary as a target site for feedback inhibition also was demonstrated.

Effects of receptor blockers (methysergide, propranolol, phentolamine, yohimbine and prazosin) on desimipramine-induced pituitary hormone stimulation in humans—III. Hypothalamo-pituitary-adrenocortical axis

In this report the effects of various receptor blockers on the desimipramine (DMI)-induced cortisol (ACTH) secretion in healthy male subjects are presented. Each trial consisted of two administrations: one of DMI i.v. alone and one of DMI i.v. in combination with the respective receptor blocker, i.e. methysergide (serotonin (5-HT) receptor blocker), propranolol (beta receptor blocker), phentolamine (alpha-1/alpha-2 receptor blocker), yohimbine (alpha-2 greater than alpha-1 receptor blocker), and prazosin (alpha-1 receptor blocker). In addition, the effect of prazosin on DMI-induced ACTH stimulation was examined. DMI-induced cortisol stimulation was not significantly different after DMI alone (n = 12) from that after three days pretreatment with methysergide (12 mg p.o.) in another group of subjects (n = 12). Neither the combination of DMI plus propranolol (15 mg i.v. n = 18, incomplete block design) nor that of DMI plus phentolamine (60 mg i.v. n = 12) had a significant influence on DMI-induced cortisol secretion. Following combined administration with yohimbine (10 mg i.v.), cortisol secretion was higher compared to that after DMI alone in the same group (n = 6). DMI-induced cortisol secretion was significantly lower (p less than 0.01) following combined administration with prazosin (1 mg p.o. n = 12), as was DMI-induced ACTH secretion (p less than 0.05) in these subjects. The findings of these trials, especially those of the prazosin trial, indicate that DMI-induced stimulation of cortisol and ACTH secretion is attributable to the noradrenaline (NA) reuptake inhibiting effect of DMI, and that the stimulus is transmitted with the aid of noradrenergic alpha-1 receptors. Alpha-2 receptors possibly exert a negative influence on this effect.

Human pancreatic growth hormone-releasing factor (hpGRF): dose-response of GRF- and GH-levels.

SummarySynthetic human pancreatic growth hormone-releasing factor (hpGRF1–44) was given as an i.v. bolus to 8 healthy volunteers in 5 different dosages. Blood was collected before and up to 120 min after GRF-injection. Four subjects received only placebo, five received 3.3 µg, three 12.5 µg, four 50 µg, 5 received 100 µg, and three 200 µg hpGRF1–44.No serious side effects were recorded after hpGRF1–44. All dosages with the exception of the 3.3 µg-dosage lead to a clearcut and significant increase of GH-levels with a maximum occurring 15 to 30 minutes after hpGRF1–44. A dose-response-relationship between the injected GRF-dosage and growth hormone levels was only found from 3.3 to 50 µg hpGRF1–44. The administration of 100 or 200 µg hpGRF1–44 did not lead to a further increase of GH-levels compared to the 50-µg-dose.This was in contrast to the clearcut dose dependency of hpGRF1–44-levels measured by a specific radioimmunoassay over the whole dose range with a maximum occurring 5 minutes after the injection. The mean halftime of disappearance for the 200-µg-dose of hp-GRF1–44 was 7.6±1.7 minutes (±SE).We conclude that there is a marked heterogeneity of the GH-response to hpGRF1–44 in healthy volunteers though a dose-response-relationship over the range from 3.3 to 50 µg hpGRF i.v. could be established. The dose-response-dependency of hpGRF1–44-levels up to the 200-µg-dose indicates that the maximal GH-response is reached when 50 µg hpGRF1–44 are administered. Therefore the test for routine purposes should be performed with 50 µg or 1 µg/kg body weight i.v.

Growth hormone releasing factor (hpGRF) ― stimulation test in normal controls and acromegalic patients

Recently a growth hormone releasing factor (GRF) has been isolated from a pancreatic tumor of an acromegalic patient. This peptide with 44 aminoacids (hpGRF1–44) has been synthesized and has been shown to have growth hormone releasing property in vivo and in vitro. We have examined the growth hormone response to synthetic hpGRF1–44 in 10 normal male and 5 normal female subjects, in 4 patients with active acromegaly and in one patient with hypothalamic pituitary insufficiency. After the injection of 100 μg hpGRF1–44, growth hormone increased in all normal controls within 5–15 min from a mean basal level of 0.64 ± 0.06 ng/ml ± SE to a peak of 16.7 ± 3.3 ng/ml 30 min after hpGRF1–44. No significant side effects were recorded. All other anterior pituitary hormones showed no increase after hpGRF1–44. In addition, no significant change of blood glucose, pulse rate or blood pressure was recorded after hpGRF1–44. In 4 normal subjects the growth hormone response to 100 μg hpGRF1–44 was compared with the response to insulin-induced hypoglycemia. There was no significant difference between the maximum increase of growth hormone after hpGRF1–44 and hypoglycemia. In 3 out of 4 patients with active acromegaly 100 μ hpGRF1–44 led to a clear-cut increase with a peak value at 15 min, whereas one patient with postoperative active acromegaly showed no GH increase after 100 μg hpGRF1–44. One acromegalic was tested before and 6 weeks after incomplete transsphenoidal surgery with the same response from a lower basal level after surgery as before. One patient with hypothalamic pituitary insufficiency had no GH response after hypoglycemia, whereas 100 μg hpGRF1–44 led to a prompt increase of GH levels. Our preliminary study suggests that the administration of 100 μg hpGRF1-44 is a reliable and safe stimulation test for GH secretion in man. The value of hpGRF1–44 administration for determining the activity of acromegaly has to be established.

Intravenous Application of Ovine and Human Corticotropin Releasing Factor (CRF): ACTH, Cortisol and CRF Levels

Synthetic ovine corticotropin releasing factor (oCRF) and human CRF were given as an intravenous bolus to 6 healthy volunteers in 4 different dosages (oCRF: 25, 50, 100 and 200 micrograms) respectively, 2 different dosages (hCRF: 50 and 100 micrograms). ACTH and cortisol were measured over a 2-hour period after CRF injection. CRF immunoreactivity was measured with a newly developed homologous radioimmunoassay for both oCRF and hCRF. All CRF dosages tested led to a definite ACTH response compared to placebo control. No dose dependency of side effects was observed. Furthermore, there was no clear-cut dose response relationship between the injected CRF dosages and the maximal ACTH- and cortisol levels. However, when the area under the ACTH and cortisol-response curves after oCRF were compared a dose-response relationship emerged, which could not be demonstrated in the same way for the two hCRF dosages. Serum CRF immunoreactivity correlated to the injected dosage. The halftime of serum disappearance for oCRF was 18 min, and hCRF, 9 min. The maximal ACTH responses after injection of oCRF and hCRF were not significantly different.