Reduction of False-Negative Results in Inferior Petrosal Sinus Sampling with Simultaneous Prolactin and Corticotropin Measurement

ObjectiveTo investigate the value of prolactin as an independent marker of catheter placement to improve the diagnostic accuracy of inferior petrosal sinus sampling (IPSS) in patients with corticotropin-dependent Cushing syndrome.MethodsIn this retrospective cohort study, we reviewed hospital records of patients who underwent IPSS procedures at the Cleveland Clinic between 1997 and 2009. Serum prolactin and plasma corticotropin levels were measured prospectively in peripheral and inferior petrosal sinus (IPS) samples.ResultsForty-one patients underwent 42 IPSS procedures at our institution during the study period. Among35 patients with Cushing disease, 1 patient had erroneous IPSS results: all pre-corticotropin-releasing hormone (CRH) and post-CRH IPS to peripheral (IPS:P) ACTH ratios were less than 2 and less than 3, respectively. Despite radiologic evidence of appropriate IPS catheter placement, concurrent IPS:P prolactin ratios indicated that successful IPS venous sampling was not achieved. A second case with equivocal IPSS results could also be explained by corresponding IPS:P prolactin ratios. During IPSS, all patients with an identifiable ACTH-staining adenoma localizing to 1 side of the pituitary gland (n = 22) who demonstrated absent IPS:P ACTH gradients (< 2 before or < 3 after CRH administration) on the ipsilateral side of the corticotroph adenoma had corresponding IPS:P prolactin ratios less than 1.3.ConclusionsMeasurement of prolactin during IPSS testing may reduce false-negative results in patients with Cushing disease who do not demonstrate an appropriate central-to-peripheral ACTH gradient. In our series, all false-negative IPS:P ACTH ratios had a corresponding IPS:P prolactin ratio less than 1.3. (Endocr Pract. 2011;17:33-40)     

A Dual Pathway for Acth Steroidogenic Action in Purified Adrenocortical Cells

Abstract

Isolated adrenal fasciculata cells were purified by centrifugation through a 0-50% hyperbolic gradient of Percoll^R. The dose-dependence and kinetics of both intracellular cyclic AMP accumulation and steroido-genesis in response to ACTH_1-39 and ACTH_5-24 (corticotropin-(1-39) and corticotropin-(5-24)-peptides) were determined using purified cells. The rate of intracellular cyclic AMP formation was maximal during the first five minutes after hormone addition and remained constant or fell thereafter. Therefore intracellular cyclic AMP accumulation, assessed after 5 min., was compared with steroid output after 20 min. Maximal steroidogenesis was elicited by ACTH^5-24 without discerning a significant stimulation of intracellular cyclic AMP accumulation. ACTH_6-24 (corticotropin-(6-24)-peptide) could completely inhibit the intracellular cyclic AMP accumulation elicited by ACTH_1-39 or by ACTH_5-24 at concentrations that only partially inhibited steroidogenesis.

It is possible that there are two pathways for the steroidogenic action of ACTH, one of which is obligatorily mediated by intracellular cyclic AMP, and another which involves a different mediator.     

Cushing's Syndrome Due to Ectopic Adrenocorticotrophic Hormone Production by Olfactory Neuroblastoma

ObjectiveTo review a case of olfactory neuroblastoma (ON) with Cushing’s syndrome (CS) due to ectopic production of adrenocorticotrophic hormone (ACTH) and compare the histopathologic diagnosis, treatment modality, and prognostic factors with the literature.MethodsWe report the clinical presentation, biochemistry, imaging, histopathology, treatment, and outcome of a patient with ON. We conducted an English language literature review of CS due to ectopic ACTH production and ON.ResultsCS due to ectopic ACTH production is uncommon, and CS due to ON is extremely rare. A 19-year-old Hispanic man presented with right nasal obstruction, involuntary weight gain, and intensely pruritic skin rash. Examination revealed large, wide purple striae on both arms and the abdomen. Head magnetic resonance imaging (MRI) revealed a right ethmoid sinus enhancing mass extending into the orbit, nasal cavity, and maxillary and sphenoid sinuses. Laboratory results showed a pm cortisol level of 26 mcg/dL, a 24-hour urinary free cortisol level of 7,507 mcg, an ACTH level of 83 pg/mL, and nonsuppression of cortisol with an overnight dexamethasone suppression test (1 and 8 mg). A biopsy revealed ON, and immunohistochemistry (IHC) was positive for ACTH. He underwent chemotherapy followed by surgical debulking and adjuvant radiation therapy, with no disease recurrence through the last follow-up in February 2012. Plasma and urinary cortisol levels normalized following surgery.ConclusionThis is the first case reported of a Hispanic male with an uncommon tumor (ON) and an even more uncommon presentation, ectopic ACTH production causing CS. The extremely high ACTH levels and plasma and urine cortisol levels dramatically dropped following multimodality management. So far, he has had 2.5 years of disease-free survival. (Endocr Pract. 2014;20:e47-e52)     

Venous Sampling for Cushing Disease: Comparison of Internal Jugular Vein and Inferior Petrosal Sinus Sampling

Objective: Because magnetic resonance imaging (MRI) fails to detect many adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas, inferior petrosal sinus sampling (IPSS) is considered the gold standard to differentiate Cushing disease (CD) from ectopic ACTH secretion syndrome (EAS). Some authors have suggested internal jugular vein sampling (IJVS) as an alternative to IPSS.Methods: We simultaneously compared IJVS to IPSS in 30 consecutive patients referred for ACTH-dependent Cushing syndrome and equivocal MRI exams. Five sites were simultaneously sampled in each patient (right and left IPS, right and left IJV, and femoral vein) before and after the administration of corticotrophin-releasing hormone or desmopressin. The test was considered consistent with CD when the IPS to peripheral ratio was >2 at baseline or >3 after stimulus and the IJV to peripheral ratio was >1.7 at baseline or >2 after stimulus.Results: In 27 of 30 patients, IPSS results were consistent with a central source of ACTH. Two of the other 3 patients had EAS (one lung carcinoid and one occult), and 1 patient had pathology-proven CD. The sensitivity of IPSS was 96.4%. Only 64.2% of these patients had results meeting criteria for a central source of ACTH by IJVS criteria. Twenty patients with centralizing IPPS have undergone pituitary surgery. Of these, the central origin of excessive ACTH was confirmed with certainty in 16 patients. Among these 16 patients, the IPSS sensitivity was 93.8%, whereas 5 patients had false-negative IJVS (68.7% sensitivity).Conclusion: These results do not support the routine use of IJVS in establishing if the pituitary is the source of excessive ACTH.Abbreviations:ACTH = adrenocorticotropic hormoneCD = Cushing diseaseCRH = corticotrophin-releasing hormoneCS = Cushing syndromeDDAVP = desmopressinEAS = ectopic ACTH secretionIJVS = internal jugular vein samplingIPSS = inferior petrosal sinus samplingJVS = jugular venous samplingMRI = magnetic resonance imaging     

Intracerebroventricular ACTH activates the pituitary-adrenal system:dissociation from a behavioral response.

In the rat, intracerebroventricular injection of synthetic ACTH (ACTH_1–24, ACTH_1–16) elevated plasma corticosterone levels and induced the display of excessive grooming behavior. The grooming response could be elicited in hypophysectomized rats without concommittant elevation of plasma corticosterone. In intact rats subcutaneous injection of ACTH_1–24 and not of ACTH_1–16-NH₂ stimulated the release of adrenal corticosteroids, whereas no excessive grooming was observed. In contrast to the reduced effectiveness of a second icv injection of ACTH in inducing the behavioral response, no single-dose tolerance was observed for the effect of icv ACTH on the pituitary-adrenal system. Therefore it was concluded that two different central mechanisms underly the observed responses to the icv applied ACTH.     

In vitro mitogenic and steroidogenic effects of ACTH analogues on an adrenal tumor cell line (Y-1)

Native porcine adrenocorticotropin (ACTH_1–39) as well as synthetic adrenocorticotropin (ACTH_1–24) increase cAMP and steroid production and inhibit DNA synthesis in an adrenal cell line. The COOH terminal sequence of both peptides as well as β-endorphin have no effects, while the NH₂ terminal sequence of ACTH as well as α-MSH which have very low stimulatory effect on cAMP production, have a mitogenic effect. These results suggest that ACTH might have in vitro some mitogenic action on adrenal cell, but this effect is blunted by cAMP accumulation during hormonal stimulation. The results can also explain the in vivo and in vitro contradictory effects of the hormone on adrenal cell replication.     

Pituitary Mri Findings in Patients With Pituitary and Ectopic Acth-Dependent Cushing Syndrome: Does A 6-Mm Pituitary Tumor Size Cut-Off Value Exclude Ectopic Acth Syndrome?

Objective: Expert opinion and a consensus statement on Cushing syndrome (CS) indicate that in a patient with a clinical presentation and biochemical studies consistent with a pituitary etiology, the presence of a pituitary tumor ≥6 mm is highly suggestive of Cushing disease (CD). The purpose of the present study was to determine the optimal pituitary tumor size that can differentiate between patients with CD and ectopic adrenocorticotrophic hormone (ACTH) secretion (EAS) and obviate the need for inferior petrosal sinus sampling (IPSS).Methods: We performed a retrospective study of 130 patients seen between 2000 and 2012 including 104 patients with CD and 26 patients with EAS.Results: A pituitary lesion was reported in 6/26 (23%) patients with EAS and 71/104 (68.3%) patients with CD, with median (range) sizes of 5 mm (3–14) and 8 mm (2–31), respectively. All tumors in the EAS group measured ≤6 mm except for 1 that measured 14 mm. The presence of a pituitary tumor >6 mm in size had 40% sensitivity and 96% specificity for the diagnosis of CD. ACTH levels >209 pg/mL and serum potassium <2.7 mmol/L were found in patients with EAS. All patients with EAS had a 24-hour urine free cortisol (UFC) >3.4 times the upper limit of normal (×ULN)Conclusion: Pituitary incidentalomas as large as 14 mm in size can be seen in patients with EAS. However, the 6-mm tumor size cut-off value provided 96% specificity and may be a reasonable threshold to proceed with surgery without the need for IPSS when the biochemical data support a pituitary etiology.Abbreviations: ACTH = adrenocorticotropic hormone CD = Cushing disease CRH = corticotropin-releasing hormone CS = Cushing syndrome EAS = ectopic ACTH secretion IPSS = inferior petrosal sinus sampling HDDST = high-dose dexamethasone suppression test LDDST = low-dose dexamethasone suppression test MRI = magnetic resonance imaging UFC = urine free cortisol ULN = upper limit of normal     

Characterization of Corticotropin-Releasing Hormone Binding Sites in the Human Placenta

Abstract

The human placenta synthesizes and secretes large amounts of corticotropin-releasing hormone (CRH) which has been implicated in the triggering of parturition. The placental CRH was found to act in a paracrine manner to stimulate secretion of ACTH and β-endorphin. In view of this we sought to characterize CRH binding sites in the human placenta.

The specific binding of ¹²⁵I-tyrosyl-ovine CRH (¹²⁵I-oCRH) to placental membranes was dependent on time, temperature, pH, divalent cations and was reversible on addition of excess oCRH. Scatchard analysis revealed a high affinity binding site with a dissociation constant of ?0.7 nmol/L and maximum number of binding sites ?44 fmol/mg protein.

Disuccinimidyl suberate, a chemical cross-linker, was used to covalently attach ¹²⁵I-oCRH to placental membranes. The labelled placental membranes were analyzed by SDS-PAGE and autoradiography. A major radioactively labelled band with a molecular weight of 55,000 Da was identified.

In this study we have identified placental binding sites for CRH with properties similar to CRH receptors described in a number of human and animal tissues and with a molecular weight similar to that of the brain CRH receptor. These binding sites may be involved in the regulation of the placental CRH/ACTH - β-endorphin axis during pregnancy and parturition.     

Effects of peptides of pituitary origin on the formation of C21 steroid by fetal calf adrenal cells in culture.

Corticotrophic activity of opiate-like peptides was assessed by their ability to stimulate the formation of C₂₁ steroids from [³H] progesterone by three-day old cultures of fetal calf adrenal cells. ACTH_1–39, ACTH_α1–24 and a purified preparation of pituitary ovine β-endorphin caused a marked increase in 17α and 21-hydroxylation while a preparation of pure synthetic porcine β-endorphin gave a minimal stimulation. The activity of the purified ovine β-endorphin preparation could not be accounted for by contamination by ACTH or by a synergistic action between the two peptides. The novel pituitary factor described here may be due to a contaminant of the β-endorphin peak which is different from ACTH_1–39.     

Behavioral and biochemical responses of mice to the intraventricular administration of ACTH analogs and lysine vasopressin.

ACTH_1?24, ACTH_4?10, ACTH_4?10(D-phe), lysine vasopressin (LVP) or an amino acid mixture were administered to mice using bilateral intraventricular injections (5×10^?9 moles per mouse). Behavioral observations were made for the subsequent 85 minutes, and the incorporation of subcutaneously injected [³H]lysine into brain proteins assayed for the last 10 minutes of this period. Mice injected with ACTH_1?24 showed the previously reported stretching and yawning syndrome, an effect also observed with ACTH_4?10(D-phe) but less often. These same peptides also induced a pronounced increase in the proportion of time mice spent grooming. LVP caused a dramatic hyperactivity; mice so injected moved continously about the cage occasionally eating or grooming, but were never still. Injection with ACTH_1?24 or ACTH_4?10(D-phe), but not ACTH_4?10 or LVP, caused significant increases in the incorporation of [³H]lysine into brain protein.     

Stimulatory effect of oCRH on alpha-subunit secretion during petrosal sinus sampling in patients with Cushing's disease.

During bilateral and simultaneous venous sampling of the inferior petrosal sinuses for preoperative localization of ACTH secreting microadenomas, alpha-subunit levels, in addition to ACTH, were determined in 9 patients with Cushing's disease. The aim of the study was to evaluate the possible occurrence of unilateral increases of alpha-subunit in basal conditions and the alpha-subunit responsiveness to oCRH. All the patients examined showed a central to peripheral and an intersinus gradient of ACTH concentrations before and/or after oCRH stimulation. Seven patients showed a central to peripheral alpha-subunit gradient in basal conditions. Lateralization of alpha-subunit concentrations was recorded in 4 patients in basal conditions (intersinus gradient > or = 1.55) and paralleled the side with the highest ACTH concentrations. After oCRH stimulation all but one patient showed a unilateral alpha-subunit increase in blood from the inferior petrosal sinus with the highest oCRH stimulated ACTH increase. The present data confirm the occurrence of an increase of alpha-subunit concentration in response to nonspecific stimulation with exogenously administered oCRH, concurrent with an ipsilateral increase of ACTH levels. The mechanism underlying this finding is still unclear, although a paracrine effect from the corticotroph tumour on adjacent pituitary tissue seems so far the most likely explanation.     

广泛性焦虑障碍患者人格特征与免疫功能、甲状腺激素和神经内分泌激素的相关性分析

摘要 目的：探讨广泛性焦虑障碍（GAD）患者人格特征与免疫功能、甲状腺激素和神经内分泌激素的相关性。方法：选择2019年1月~2020年12月北部战区空军医院心理科收治的GAD患者80例作为研究组,选择同期于北部战区空军医院体检的健康志愿者80例作为对照组。应用艾森克人格问卷简式量表中国版（EPQ-RSC）对受试者人格特征进行评价,比较两组EPQ-RSC评分结果、血液中CD3⁺、CD4⁺、自然杀伤细胞（NK）比例,血清白细胞介素（IL）-2、IL-6,三碘甲状腺原氨酸（T3）、甲状腺素（T4）、游离三碘甲状腺原氨酸（FT3）、游离甲状腺素（FT4）、促甲状腺激素（TSH）、去甲肾上腺素（NE）、促肾上腺皮质激素（ACTH）、皮质醇（CS）水平,并分析其相关性。结果：研究组精神质（P）、神经质（N）评分及EPQ-RSC总分均显著高于对照组（P<0.05）,研究组CD3⁺、CD4⁺、NK比例显著低于对照组,血清IL-2、IL-6水平显著高于对照组（P<0.05）。研究组血清FT3、FT4水平显著低于对照组（P<0.05）。研究组血清CS水平显著低于对照组,NE、ACTH水平显著高于对照组（P<0.05）。Pearson相关分析显示,GAD患者N、P评分及EPQ-RSC总分与CD3⁺、CD4⁺、NK、FT3、FT4、CS呈负相关（P<0.05）,与IL-2、IL-6、NE、ACTH呈正相关（P<0.05）。结论：GAD患者存在免疫功能损伤、神经内分泌激素和甲状腺激素水平异常,且均与患者P、N倾向的人格特征有关。     

Multiple forms of ACTH biological activity in the pars intermedia of the rat adenohypophysis.

Acid extracts of a) acutely dispersed rat pars intermedia (PI) cells, b) media after incubation of PI cells, c) whole nervosa-intermedia, and d) whole pars distalis, were chromatographed on Sephadex G-50 Fine in 1% acetic acid. Three peaks of ACTH biological activity were resolved in all four extracts. Peak I eluted in the void volume of the column, peak III co-eluted with synthetic ACTH^1–39, and peak II eluted in an intermediate position. The predominant ACTH activity derived from the PI tissue was peak I, amounting to over 70% of the total ACTH activity present in that lobe. The positions of PI peaks I and II remained unaltered after rechromatography as well as after treatment with and chromatography in 8 M urea. However, peak I of PI ACTH was further resolved into two separate peaks by chromatography on Sephadex G-100 SF. Thus pars intermedia ACTH activity appears to be composed of four separate entities, with the predominant forms being larger than ACTH^1–39.     

ACTH-dependent stimulation of a specific peptide in adrenocortical cells in culture.

Corticotropin (1–24) tetracosapeptide (ACTH_1–24) induces a small but significant increase in the incorporation of radioactive leucine into trichloracetic insoluble proteins of a mouse adrenal cell line Y₁. Neither cyclic AMP, nor cholera toxin or a nitrophenyl sulfenyl derivative of ACTH_1–24 (NPS-ACTH_1–24) have any effects.After being labelled with radioactive leucine in the presence or absence of ACTH, the cells were solbilized in 1 % sodium dodecylsulfate and subjected to 20 % sodium dodecylsulfate polyacrylamide gels electrophoresis. ACTH_1–24 was found to induce a dramatic increase in the incorporation of radioactive leucine into a small peptide (MW 3500). This effect was mimicked by other steroidogenic compounds such as cholera toxin, cyclic AMP, NPS-ACTH_1–24 but not by ACTH_11–24, a non steroidogenic analogue of ACTH.     

Testosterone potentiation of the effectiveness of ACTH1-24 on the induction of the stretch-yawning syndrome (SYS) in male guinea pigs

Ventricular administration of ACTH^1–24 stimulated stretch-yawning in castrated male guinea pigs in a dose-related manner. Daily subcutaneous treatment with testosterone propionate (TP) facilitated the effects of ACTH^1–24 on this response. TP given without ACTH^1–24 stimulated yawning, but not stretching or combined stretch-yawning. Unlike most other species, guinea pigs did not display auto-grooming, scratching, or wet-dog shaking in response to intracranial ACTH^1–24. The results suggest that testosterone may alter the sensitivity of neural mechanisms which are responsive to ACTH^1–24.     

Ectopic Acth-Secreting Syndrome: A Single-Center Experience

ObjectiveEctopic adrenocorticotropic hormone (ACTH)-secreting syndrome (EAS) is a rare cause of ACTH-dependent endogenous hypercortisolism. The objective of this study was to analyze clinical, biochemical, and imaging characteristics; management strategies; and outcomes of EAS patients.MethodWe screened the records (1993-2012) of ACTH-dependent endogenous hypercortisolism cases managed at a tertiary care center.ResultsOf the 218 patients, 17 were diagnosed with EAS. The median 8:00 AM serum cortisol was 36 μg/dL (11.4-82.7 μg/dL), and the median basal plasma ACTH was 156 pg/mL (53.5-468 pg/mL). Notably, ACTH levels below 100 pg/mL were found in 4 patients. Suspicious microadenoma was found on magnetic resonance imaging (MRI) of the pituitary in 5 patients, and all of them underwent transsphenoidal surgery (TSS). Inferior petrosal sinus sampling (IPSS) was performed in 8 patients, and the results were suggestive of a peripheral source in all 8. Computed tomography (CT) localized the lesion in 15/17 patients. In 2 patients with negative CTs, gallium DOTATATE positron emission tomography (PET) scans localized the lesion. Despite difficulties localizing bronchial carcinoids, the cure rate was high (72%). In contrast, thymic carcinoids were easily localized but had poor outcomes.ConclusionEAS cannot be ruled out on the basis of marginally elevated ACTH. In cases with an equivocal MRI pituitary finding, prior IPSS can help avoid unnecessary TSS. CT is a useful modality for localization of an ectopic source. Functional imaging may help in cases where anatomical imaging fails. (Endocr Pract. 2013;19:1007-1014)     

Inhibition of ACTH-stimulated steroidogenesis in isolated rat adrenal cells treated with neuraminidase

The possible role of membrane sialic acid in the action of ACTH was investigated in rat adrenal cells. After treatment with neuraminidase, the cells showed a diminished steroidogenic response to ACTH while the response to cyclic AMP and dibutyryl cyclic AMP was unaffected. 11β-hydroxylation of deoxycorticosterone (DOC) was also not impaired. Dose response curves for three ACTH peptides (ACTH_1–39′, ACTH_1–24 and ACTH_1–10) with neuraminidase treated cells suggest that sialic acid residues on the glycoproteins of the plasma membrane may either impart affinity to the plasma membrane for ACTH molecule or facilitate transmission of the signal arising from ACTH-receptor interaction to the catalytic site of adenyl cyclase.     

The effect of theophylline on adenosine 3′, 5′-monophosphate-dependent protein kinase and ACTH1–24 stimulated steroidogenesis in bovine adrenal cortical cells

Theophylline (theo), a known phosphodiesterase (PDE) inhibitor, was tested for its effects on ACTH_1–24 regulated steroidogenesis in isolated bovine adrenal cortical cells. Theo produced a dose related inhibition of ACTH_1–24 stimulated cortisol synthesis with half maximal inhibition occuring at 7 mM. Theo enhanced ACTH_1–24 stimulated cellular adenosine 3′, 5′-monophosphate (cAMP) levels above that produced by ACTH_1–24 alone confirming its inhibition of cAMP PDE. When tested on cAMP binding protein and cAMP-dependent protein kinase activities in cytosol prepared from bovine adrenal cortex, theo displaced ³H-cAMP binding to cAMP binding protein and inhibited cAMP-stimulated protein kinase activity. The half maximal inhibition of cAMP binding and protein kinase activity was observed at 10 and 5 mM, respectively. Inhibition of cAMP-dependent protein kinase by theo provides a possible explanation of its inhibitory effects on adrenal steroidogenesis and further implicates cAMP-dependent protein kinase in mediating ACTH stimulated steroidogenesis. Furthermore these studies suggest a novel mechanism of action for theo in addition to its known action on cAMP PDE.     

Isolated adrenal cortex cells: ACTH agonists, partial agonists, antagonists; cyclic AMP and corticosterone production

Isolated adrenal cortex cells respond to the addition of ACTH_1–39 or analogs with increased production of cyclic AMP and corticosterone. It is estimated that cyclic AMP production need proceed at less than 20% of maximum to induce maximum corticosterone production. ACTH_1–24, [Lys¹⁷, Lys¹⁸]ACTH_1–8 amide, and ACTH_1–16 amide induce a maximum rate of cyclic AMP and of corticosterone production equal to those of ACTH_1–39. The relative potencies as determined by cyclic AMP and by corticosterone production are in excellent agreement. The analog, ACTH_5–24, induces maximum cyclic AMP production equal to 45% of that of the natural hormone, but as predicted, induces maximum corticosterone production equal to that of ACTH_1–39. The derivative, [Trp(Nps)⁹]ACTH_1–39 induces 77% of maximum corticosterone production and less than 1% of maximum cyclic AMP production. The fragment ACTH_11–24 is a competitive antagonist of ACTH_1–39 for both cyclic AMP and corticosterone production. The observations on agonists, a partial agonist and a competitive antagonist are in harmony with the “second messenger” role assigned to cyclic AMP. A provisional model, based on the fit of the experimental observations to a set of equations, provides expressions of “intrinsic activity,” “receptor reserve”, “sensitivity”, and “amplification” in terms of maximum cyclic AMP production, concentration of ACTH which induces $\text{1}\text{2}$ maximum cyclic AMP production and concentration of cyclic AMP which induces $\text{1}\text{2}$ maximum corticosterone production.     

Adrenocorticotropic hormone (ACTH)-lipid interactions. Implication for involvement of amphipathic helix formation

ACTH-lipid interactions were investigated by: (1) lipid-monolayer studies using several zwitterionic and anionic phospholipids and gangliosides, (2) permeability experiments by following the swelling rate of liposomes in isotonic glycerol solutions by light scattering, using liposomes of synthetic lipids and liposomes made of lipids extracted from light synaptic plasma membranes, and (3) by steady-state fluorescence anisotropy measurements on liposomes derived from light synaptic plasma membranes employing 1,6-diphenyl-1,3,5-hexatriene as fluorescent probe. (1) The monolayer experiments demonstrated an interaction with gangliosides G_T1, G_M1, dioleoylphosphatidic acid and phosphatidylserine, but little or no interaction with phosphatidylcholine or sphingomyelin. The interaction with monolayers of G_T1 or phosphatidic acid decreased for ACTH_1-13-NH₂ and ACTH_1-10. (2) The liposome experiments showed that $\text{2·10}{}^{\mathrm{?5}}$ M ACTH_1–24 increased the glycerol permeability by 20% and decreased the activation energy only when liposomes derived from light synaptic plasma membranes were used. Treatment of the liposomes with neuraminidase abolished the ACTH-induced permeability increase. (3) Steady-state fluorescence depolarization measurements revealed that ACTH_1–24, ACTH_1-16-NH₂ and ACTH_1–10 did not change the fluidity of liposomes derived from light synaptic plasma membranes as sensed by diphenylhexatriene. It is concluded that ACTH_1–24 can bind to negatively charged lipids and can form an amphipathic helix aligned parallel to the membrane surface involving the N-terminal residues 1 to 12, possibly to 16. Polysialogangliosides will favorably meet the condition of a high local surface charge density under physiological circumstances. It is suggested that ACTH-ganglioside interactions will participate in ACTH-receptor interactions.