A B S T R A C T Synthetic ovine corticotropin-releasing factor (CRF) was administered to normal male volunteer subjects as an intravenous bolus or 30-s infusion. Doses of CRF ranging from 0.001 to 30 sg/kg body wt were administered, and plasma immunoreactive (IR)-ACTH and IR-cortisol concentrations were measured. The threshold dose appeared to be 0.01-0.03 ag/kg, the half-maximal dose 0.3-1 sg/kg, and the maximally effective dose 3-10 ug/kg. Basal concentrations of IR-ACTH and IR-cortisol were 14±7.6 pg/ ml (mean±SD) and 5.6±2.2 gg/dl, respectively. IR-ACTH rose as early as 2 min after CRF injection, reached peak levels in 10-15 min, and declined slowly thereafter. IR-cortisol rose at 10 min or later and reached peak levels in 30-60 min. At a dose of 30 jig/ kg, neither IR-ACTH nor IR-cortisol fell from peak levels of 82±21 pg/ml (mean±SE) and 23±1.4 ,g/dl, respectively, during the 2-h course of the experiment, indicating that CRF has a sustained effect on ACTH release and/or a prolonged circulating plasma halflife. There was little or no increase in the levels of other anterior pituitary hormones. At doses of 1 gg/ Preliminary results of these studies were presented by Dr.

Post-traumatic stress disorder (PTSD) is reported in some studies to be associated with increased glucocorticoid (GC) sensitivity. Two common glucocorticoid receptor (GR) polymorphisms (N363S and BclI) appear to contribute to the population variance in GC sensitivity. There is some evidence that there may be a genetic predisposition to PTSD. Hence we studied 118 Vietnam war veterans with PTSD for (i) GR polymorphisms, particularly the N363S and the BclI polymorphisms which are thought to be GC sensitising, and (ii) two measures of GC sensitivity, the low-dose 0.25 mg dexamethasone suppression test (LD-DST) and the dermal vasoconstrictor assay (DVVA). The DST and GR polymorphisms were also performed in 42 combat exposed Vietnam war veterans without PTSD. Basal plasma cortisol levels were not significantly different in PTSD (399.5+/-19.2 nmol/L, N=75) and controls (348.6+/-23.0 nmol/L, N=33) and the LD-DST resulted in similar cortisol suppression in both groups (45.6+/-3.2 vs. 40.8+/-4.1%). The cortisol suppression in PTSD patients does not correlate with Clinician Administered PTSD Scores (CAPS), however there was a significant association between the BclI GG genotype and low basal cortisol levels in PTSD (P=0.048). The response to the DVVA was similar to controls (945+/-122, N=106 vs. 730+/-236, N=28, P=0.42). PTSD patients with the GG genotype, however, tended to be more responsive to DVVA and in this group the DVVA correlated with higher CAPS scores. The only exon 2 GR polymorphisms detected were the R23K and N363S. Heterozygosity for the N363S variant in PTSD, at 5.1% was not more prevalent than in other population studies of the N363S polymorphism in Caucasians (6.0-14.8%). The GG genotype of the BclI polymorphism found to be associated with increased GC sensitivity in many studies showed a tendency towards increased response with DVVA and correlated with higher CAPS scores. In conclusion, the N363S and BclI GR polymorphisms were not more frequent in PTSD patients than controls and reported population frequencies. Our PTSD group did not display GC hypersensitivity, as measured by the LD-DST and DVVA. In a subset of PTSD patients with the BclI GG genotype, CAPS scores and basal cortisol levels were negatively correlated.

A bstract. Arginine vasopressin (AVP) stimulates ACTH release in man and acts synergistically with synthetic ovine corticotropin-releasing factor (oCRF) in vitro. This study was designed to examine in man the combined effects of synthetic AVP (10 U intramuscularly) and oCRF (1 gg/kg intravenously) on ACTH release.Five normal male volunteers participated in five separate experiments: (a) AVP alone; (b) oCRF alone; (c) AVP followed by oCRF 15 min later; (d) simultaneous AVP and oCRF; and (e) insulin-induced hypoglycemia. Plasma immunoreactive ACTH (IR-ACTH) and IR-cortisol were measured for 4 h after injection of each hormone; basal levels for all subjects were .9±1.2 pg/ml and 4. 9±0.4 ,gg/dl (mean±SE), respectively. AVP and oCRF, when given individually, caused rapid rises in IR-ACTH to similar peak levels of 25±6.6 and 33±4.6 pg/ml, respectively. AVP given 15 min before oCRF caused a 2.6-fold potentiation ofthe oCRF response, with a peak IR-ACTH of 85±4.6 pg/ml. AVP given at the same time as oCRF produced a fourfold potentiation of the peak IR-ACTH response to 132±11 pg/ml. These ACTH responses were far greater than those previously observed after 30-fold greater doses of oCRF alone. By way of comparison, insulin-induced hypoglycemia caused a peak IR-ACTH of 169±20 pg/ml. IR-ACTH returned to base line at 60-90 min after AVP alone, whereas the prolonged effect of oCRF was apparent whether it was given alone or in combination with AVP. The mean peak IR-cortisol responses to AVP, oCRF, and AVP given 15 min before oCRF were similar (16.5±0.9, 16.4±2.3, and 18.5±0.8 ,ug/dl, respectively), but the peak IR-cortisol responses to AVP and oCRF given simultaneously and to insulininduced hypoglycemia were 1.5 and 1.7 times greater, respectively. IR-cortisol returned to base line within 2-3 h after AVP alone, but remained elevated for at least 4 h after oCRF alone or in combination with AVP. These results indicate that AVP acts synergistically with oCRF to release ACTH in man and suggest that AVP may play a physiologic role in modulating the ACTH response mediated by corticotropin-releasing factor.

Corticotropin-releasing factor (CRF) was administered as an iv bolus to two young women with mild Cushing's disease shortly before and one week after successful transsphenoidal microadenomectomy. The dose of CRF (1 microgram/kg body weight) had previously been shown to stimulate increased plasma ACTH and cortisol in normal subjects. In the first patient, prior to surgery, there were brisk increases in ACTH and cortisol that exceeded those observed in normal subjects. ACTH rose by 2 min and reached a peak between 15-30 min. Cortisol increased by 10 min and peaked between 45-60 min. After surgery, at a time when plasma cortisol was maintained at similar levels with exogenous hydrocortisone, there was no plasma ACTH or LH, TSH and prolactin increased after administration of LRH and TRH, and GH increased in response to insulin-induced hypoglycemia. The second patient had higher basal plasma ACTH and cortisol than the first patient. CRF-induced increments in ACTH and cortisol were much less, but the time course was similar and peak levels attained were still higher than those in normal subjects. After surgery, at a time when plasma cortisol was maintained at a much lower level with exogenous hydrocortisone, there was no plasma ACTH or cortisol response. She had mild, transient diabetes insipidus. Basal levels of all other anterior pituitary hormones were normal. These results demonstrate that two microadenomas causing Cushing's disease were responsive to CRF in situ and suggest that CRF may be involved in the etiology and/or the responses to changes in plasma glucocorticoid concentrations observed in patients with Cushing's disease.

Readily detectable levels of renin activity were demonstrated in human adrenal tissues. This activity was inhibited by specific antibody raised against pure renin, indicating that it was not due to the nonspecific action of proteases. The renin activity was predominantly in the cortex rather than in the medulla of the adrenal. An adrenal gland that was surgically removed from a patient with Cushing's disease and had high renin activity was used for further characterization of the enzyme. It shared many biochemical features with kidney renin, such as molecular weight, isoelectric point, glycoprotein nature, optimum pH of enzyme activity, affinity to pepstatin, and the presence of trypsin-activatable inactive renin. The lack of correlation between PRA and the adrenal renin, and the particulate localization of the subcellular distribution of adrenal renin suggested its local origin rather than contamination or contribution of the plasma enzyme.