Early rise in blood pressure following administration of adrenocorticotropic hormone-[1-24] in humans

Comparison of Bolus and Continuous Infusion of Adrenocorticotropic Hormone During Adrenal Vein Sampling

BACKGROUND

Adrenocorticotropic hormone (ACTH) is widely used in adrenal vein sampling (AVS) and can be administered as a bolus injection or continuous infusion. The optimal administration method has not been determined. We aimed to compare the effects of ACTH bolus with infusion on cannulation success, lateralization assessment and adverse events (AEs).

METHODS

Retrospectively collected data from patients with primary aldosteronism who underwent AVS with ACTH at a tertiary hospital in China. Rate of successful cannulation, lateralization index (LI), complete biochemical remission and AEs related to AVS were analyzed.

RESULTS

The study included 80 patients receiving ACTH bolus and 94 receiving infusions. The rate of successful cannulation was comparable between bolus and infusion groups (75/80, 93.4% vs 88/94, 93.6%). In those with successful cannulation, the bolus group had a higher selectivity index than the infusion group, while LI [6.4(1.8-17.5) vs. 7.6(2.0-27.8), P=0.48] and rate of complete biochemical remission (43/44, 97.7% vs 53/53, 100%, P=0.45) did not significantly differ between the two groups. One in the bolus and one patient in the infusion group had adrenal vein rupture but they recovered with conservative treatment. The bolus group reported more transient AEs such as palpitation (52.9% vs 2.2%) and abdominal discomfort (40.0% vs 2.2%) than the infusion group.

CONCLUSIONS

Due to their similar effects on cannulation success and lateralization, but a lower rate of transient AEs in the infusion group, the continuous infusion method should be recommended for ACTH stimulation in AVS.

Acute Effects of Glucocorticoids on Endothelial Fibrinolytic and Vasodilator Function in Humans

Acute coronary events occur most commonly in the morning, when circadian variations dictate that endogenous fibrinolytic activity is low and cortisol levels are high. We hypothesized that glucocorticoids would impair the acute fibrinolytic capacity of the endothelium because chronic glucocorticoid excess is associated with a prothrombotic state and endothelial vasomotor dysfunction. Twelve healthy subjects attended on 3 occasions and received oral metyrapone followed by intravenous saline or low-dose or high-dose hydrocortisone. Forearm blood flow and fibrinolytic indices were measured using venous occlusion plethysmography during intrabrachial bradykinin, acetylcholine, and sodium nitroprusside infusion. Hydrocortisone infusion had no effect on systemic concentrations of plasminogen activator inhibitor type 1 (PAI-1) or tissue plasminogen activator (t-PA; P = 0.10 and 0.95, respectively). Bradykinin caused a dose-dependent increase in plasma t-PA concentrations (P < 0.0001) that was unaffected by systemic hydrocortisone administration. Intrabrachial infusions of bradykinin, acetylcholine, and sodium nitroprusside all caused dose-dependent increases in forearm blood flow (P < 0.05) that were unaltered by hydrocortisone infusions.Short-term variations in plasma cortisol concentrations within the physiological range do not affect endothelial fibrinolytic or vasomotor function in healthy volunteers. These findings suggest that glucocorticoids do not exert acute effects on endothelial function in vivo in humans.

Species variability in cardiovascular research: the example of adrenocorticotrophin-induced hypertension

1. Lawrie Beilin has contributed greatly to international hypertension research through both animal and human studies. 2. Animals are used in biomedical research to gain insights that can be extrapolated ultimately to humans. 3. A simple experimental manipulation, adrenocorticotrophin (ACTH) administration, has a range of different cardiovascular effects in different species. 4. Caution should be exercised in extrapolating data from animals to humans.

Acute effects of hydrocortisone on plasma nitrate/nitrite activity and forearm vasodilator responsiveness in normal human subjects

1. The aim of the present study was to examine the acute effects of cortisol infusion on plasma nitrate/nitrite (NO) activity and forearm vascular responsiveness to acetylcholine. 2. We performed two randomized, placebo-controlled, cross-over studies. Study A examined the effects of intravenous hydrocortisone (200 mg over a 3 h period) on blood pressure (BP) and plasma NO activity in six healthy male volunteers. Study B examined the effects of intra-arterial hydrocortisone on cholinergic vasodilator responsiveness in six healthy male volunteers. Vasodilator responsiveness was measured by bilateral strain gauge plethysmography. 3. In study A, there was no significant change in BP during the hydrocortisone infusion. Comparing values obtained following 180 min infusion of hydrocortisone and control, there were significant increases in plasma cortisol (3441 +/- 342 vs 209 +/- 29 nmol/L, respectively; P < 0.001) and glucose (5.7 +/- 0.2 vs 4.6 +/- 0.2 mmol/L, respectively; P < 0.05) and a reduction in plasma renin concentration (PRC) (8.1 +/- 1.2 vs 11.0 +/- 1.8 pg/mL, respectively; P < 0.05) following hydrocortisone infusion. However, there were no significant changes in either plasma NO or in the endogenous NO synthase inhibitors asymmetrical and symmetrical dimethylarginine. 4. In study B, there was no significant change in BP or in cholinergic vasodilator responsiveness during the hydrocortisone infusion. 5. Short-term cortisol infusions do not alter biochemical or physiological markers of NO activity. If cortisol-induced hypertension is mediated by suppression of NO activity in humans, it seems likely that these changes take more than 3 h to become detectable.

Cardiovascular effects of long-term central and peripheral administration of urocortin, corticotropin-releasing factor, and adrenocorticotropin in sheep

The neuroendocrine hormones ACTH and corticotropin- releasing factor (CRF), which are involved in the stress response, have acute effects on arterial pressure. New evidence indicates that urocortin (UCN), the putative agonist for the CRF type 2 receptor, has selective cardiovascular actions. The responses to long-term infusions of these hormones, both peripherally and centrally, in conscious animals have not been studied. Knowledge of the long-term effects is important because they may differ considerably from their acute actions, and stress is frequently a chronic stimulus. The present experiments investigated the cardiovascular effects of CRF, UCN, and ACTH in conscious sheep. Infusions were made either into the lateral cerebral ventricles (i.c.v.) or i.v. over 4 d at 5 microg/h. UCN infused i.c.v. or i.v. caused a prolonged increase in heart rate (HR) (P < 0.01) and a small increase in mean arterial pressure (MAP) (P < 0.05). CRF infused i.c.v. or i.v. progressively increased MAP (P < 0.05) but had no effect on HR. Central administration of ACTH had no effect, whereas systemic infusion increased MAP and HR (P < 0.001). In conclusion, long-term administration of these three peptides associated with the stress response had prolonged, selective cardiovascular actions. The striking finding was the large and sustained increase in HR with i.c.v. and i.v. infusions of UCN. These responses are probably mediated by CRF type 2 receptors because they were not reproduced by infusions of CRF.