Ruth Rossetto Giaccherino
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Research Subjects
Ruth Rossetto Giaccherino has a total of 85 co-authors. Here are the top co-authors by number of shared publications:
- Loredana Pagano
Endocrinology, Diabetology and Metabolism, Department of Medical Sciences, University of Turin, 10128 Turin, Italy
3 shared publications - Emanuela Arvat
Division of Oncological Endocrinology, A.O.U Città della Salute e della Scienza di Torino, 10126 Turin, Italy
2 shared publications - Ezio Ghigo
Department of Medical Sciences, University of Turin, Turin, Italy
2 shared publications - Laura Fugazzola
Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
2 shared publications - Letizia Meomartino
Endocrinologia, Diabetologia e Metabolismo, Dipartimento di Scienze Mediche, Università degli Studi di Torino, Torino, Italia
2 shared publications - Loredana Pagano
Division of Endocrinology, Diabetology and Metabolism, Department of Medical Sciences, University of Turin, Turin, Italy
2 shared publications
Latest Publications
- Open Access
Adding L-Carnitine and Selenium to Methimazole in Graves’ Disease: A Prospective Randomized Trial on Thyroid Markers and Quality of Life
Background: The therapeutic response in Graves’ Disease (GD) remains largely unpredictable. Patients often experience persistent symptoms that are poorly correlated with thyroid hormone levels, an undefined treatment duration, and the need for long-term or definitive therapies. Based on the nuclear antagonistic properties of L-carnitine (LCT) on thyroid hormone action and the immunomodulatory role of selenium (Se), we aimed to assess the impact of adding a combined LCT and Se supplement to standard methimazole (MMI) therapy on the biochemical profile and quality of life (QoL) of patients with overt GD. Methods: This multicenter prospective randomized trial enrolled 60 consecutive patients with newly diagnosed overt GD. Participants were randomized to receive either standard treatment with MMI alone (Control Group) or MMI plus the combined LCT/Se supplement (Intervention Group). TSH, fT3, fT4, and TSH–receptor antibodies (TRAb) levels were evaluated every two months for up to 24 months or until spontaneous remission or definitive therapy. At each visit, patients completed a symptom questionnaire addressing the frequency of typical thyrotoxic symptoms. Results: No significant differences were observed between groups in the trend or time-to-normalization of TSH, fT3, and fT4 levels. However, the Intervention Group reached TRAb negativity significantly earlier (HR = 2.35 (1.14–4.81), p = 0.016), with a synergistic interaction with MMI therapy. MMI requirements were consistently lower in the Intervention Group, both in average dosage (p = 0.013) and cumulative dose (p = 0.020). The rate of spontaneous remission was significantly higher (OR = 11.22 (3.35–46.11), p < 0.001). Overall symptom burden did not differ significantly between groups; however, the supplement exerted an independent effect in reducing the severity of tremor, irritability, mood lability, heat intolerance, and exertional dyspnea. Conclusions: Our findings suggest the clinical benefits of adding combined LCT and Se supplementation to MMI in the treatment of overt GD, including shorter disease duration, lower cumulative MMI exposure and earlier TRAb normality, that could positively influence TRAb-related prognostic outcomes.
Open AccessAdding L-Carnitine and Selenium to Methimazole in Graves’ Disease: A Prospective Randomized Trial on Thyroid Markers and Quality of Life
Background: The therapeutic response in Graves’ Disease (GD) remains largely unpredictable. Patients often experience persistent symptoms that are poorly correlated with thyroid hormone levels, an undefined treatment duration, and the need for long-term or definitive therapies. Based on the nuclear antagonistic properties of L-carnitine (LCT) on thyroid hormone action and the immunomodulatory role of selenium (Se), we aimed to assess the impact of adding a combined LCT and Se supplement to standard methimazole (MMI) therapy on the biochemical profile and quality of life (QoL) of patients with overt GD. Methods: This multicenter prospective randomized trial enrolled 60 consecutive patients with newly diagnosed overt GD. Participants were randomized to receive either standard treatment with MMI alone (Control Group) or MMI plus the combined LCT/Se supplement (Intervention Group). TSH, fT3, fT4, and TSH–receptor antibodies (TRAb) levels were evaluated every two months for up to 24 months or until spontaneous remission or definitive therapy. At each visit, patients completed a symptom questionnaire addressing the frequency of typical thyrotoxic symptoms. Results: No significant differences were observed between groups in the trend or time-to-normalization of TSH, fT3, and fT4 levels. However, the Intervention Group reached TRAb negativity significantly earlier (HR = 2.35 (1.14–4.81), p = 0.016), with a synergistic interaction with MMI therapy. MMI requirements were consistently lower in the Intervention Group, both in average dosage (p = 0.013) and cumulative dose (p = 0.020). The rate of spontaneous remission was significantly higher (OR = 11.22 (3.35–46.11), p < 0.001). Overall symptom burden did not differ significantly between groups; however, the supplement exerted an independent effect in reducing the severity of tremor, irritability, mood lability, heat intolerance, and exertional dyspnea. Conclusions: Our findings suggest the clinical benefits of adding combined LCT and Se supplementation to MMI in the treatment of overt GD, including shorter disease duration, lower cumulative MMI exposure and earlier TRAb normality, that could positively influence TRAb-related prognostic outcomes.
- Open Access
- 1 April 2025
- Published by MDPI AG in Endocrines
- Vol. 6 (2) , 15
Ultrasound Assessment and Sexual Dimorphism of Thyroid Nodules: Bringing Gender Medicine to Clinical Practice
Background/Objectives: Understanding sex-based differences in both the pathophysiology and clinical presentation of diseases is necessary to improve health care towards precision medicine. The endocrine system is deeply involved in human health, and endocrine diseases may be influenced by steroidal hormone exposure. Thyroid nodular disease and differentiated thyroid cancer, in particular, show a high prevalence in the female sex; however, little is known about sex-related differences in risk factors and clinical presentation. This study aims to assess whether morphological differences, which can be detected by ultrasound examination, can be related to sex in order to refine diagnostic approaches and oncological risk classification. Methods: A retrospective observational study on 1355 ultrasound images of thyroid nodules obtained from 2017 to 2020 at a single university center was conducted. The images were reviewed by a single observer blinded to the patient’s sex and the cytological nature of the nodules. The qualitative description, size, anatomical location and oncological risk classification were assessed. Results: A taller-than-wide shape (anteroposterior/craniocaudal axis ratio > 1) was found to be more frequent in men than in women (6.7% vs. 3.6%, p = 0.027); the nodular volume was significantly larger in males (p << 0.01) than in females. Significant tropism for the upper lobe and isthmus was described in women (26% vs. 16.5%, p = 0.011) and for medium–lower thyroid lobes in men (83.5% vs. 73.8%, p = 0.011). Background thyroiditis was more common in women, while the number of cytological diagnoses of malignant or likely malignant nodules was higher than expected in men (9% vs. 6%, p = 0.01). Conclusions: Thyroid nodules show different distributions, in terms of a larger volume, more frequent taller-than-wide shape and lobular caudal location, in men vs. women. These results should be confirmed by further investigations, and the underlying mechanism should be clarified. However, our explorative research is of interest due to its novelty and possible future clinical implications.
- 1 April 2025
- Published by MDPI AG in Endocrines
- Vol. 6 (2) , 15
Open AccessUltrasound Assessment and Sexual Dimorphism of Thyroid Nodules: Bringing Gender Medicine to Clinical Practice
Background/Objectives: Understanding sex-based differences in both the pathophysiology and clinical presentation of diseases is necessary to improve health care towards precision medicine. The endocrine system is deeply involved in human health, and endocrine diseases may be influenced by steroidal hormone exposure. Thyroid nodular disease and differentiated thyroid cancer, in particular, show a high prevalence in the female sex; however, little is known about sex-related differences in risk factors and clinical presentation. This study aims to assess whether morphological differences, which can be detected by ultrasound examination, can be related to sex in order to refine diagnostic approaches and oncological risk classification. Methods: A retrospective observational study on 1355 ultrasound images of thyroid nodules obtained from 2017 to 2020 at a single university center was conducted. The images were reviewed by a single observer blinded to the patient’s sex and the cytological nature of the nodules. The qualitative description, size, anatomical location and oncological risk classification were assessed. Results: A taller-than-wide shape (anteroposterior/craniocaudal axis ratio > 1) was found to be more frequent in men than in women (6.7% vs. 3.6%, p = 0.027); the nodular volume was significantly larger in males (p << 0.01) than in females. Significant tropism for the upper lobe and isthmus was described in women (26% vs. 16.5%, p = 0.011) and for medium–lower thyroid lobes in men (83.5% vs. 73.8%, p = 0.011). Background thyroiditis was more common in women, while the number of cytological diagnoses of malignant or likely malignant nodules was higher than expected in men (9% vs. 6%, p = 0.01). Conclusions: Thyroid nodules show different distributions, in terms of a larger volume, more frequent taller-than-wide shape and lobular caudal location, in men vs. women. These results should be confirmed by further investigations, and the underlying mechanism should be clarified. However, our explorative research is of interest due to its novelty and possible future clinical implications.
- 27 December 2023
- Published by SAGE Publications in Thyroid®
- Vol. 34 (3) , 360-370
Clinical Outcomes of Thermal Ablation Re-Treatment of Benign Thyroid Nodules: A Multicenter Study from the Italian Minimally Invasive Treatments of the Thyroid Group
Background: Thermal ablation (TA) is an established therapeutic option alternative to surgery in patients with solid benign thyroid nodules causing local symptoms. However, a variable part of thyroid nodules remain viable after these nonsurgical treatments, and as many as 15% of nodules treated with TA may require a second treatment over time. This study aimed to evaluate the outcomes of TA re-treatment on symptomatic benign thyroid nodules where the volume decreased by 30 mL) was associated with increased risk of re-treatment (HR = 4.52 [CI 1.38–14.82]). Conclusions: This is the first study evaluating the outcomes of re-treatment on symptomatic benign thyroid nodules with a VRR <50% after the initial TA treatment. Best results were seen in small and medium nodules (<30 mL) and after RFA. Prospective confirmatory studies are needed.
- 27 December 2023
- Published by SAGE Publications in Thyroid®
- Vol. 34 (3) , 360-370
Clinical Outcomes of Thermal Ablation Re-Treatment of Benign Thyroid Nodules: A Multicenter Study from the Italian Minimally Invasive Treatments of the Thyroid Group
Background: Thermal ablation (TA) is an established therapeutic option alternative to surgery in patients with solid benign thyroid nodules causing local symptoms. However, a variable part of thyroid nodules remain viable after these nonsurgical treatments, and as many as 15% of nodules treated with TA may require a second treatment over time. This study aimed to evaluate the outcomes of TA re-treatment on symptomatic benign thyroid nodules where the volume decreased by 30 mL) was associated with increased risk of re-treatment (HR = 4.52 [CI 1.38–14.82]). Conclusions: This is the first study evaluating the outcomes of re-treatment on symptomatic benign thyroid nodules with a VRR <50% after the initial TA treatment. Best results were seen in small and medium nodules (<30 mL) and after RFA. Prospective confirmatory studies are needed.
- Open Access
- 29 April 2023
- Published by MDPI AG in Journal of Personalized Medicine
- Vol. 13 (5) , 775
Post-Surgical Indications to Radioiodine Treatment and Potential Risk Factors for Post-Treatment Recurrence in Patients with Intermediate-Risk Differentiated Thyroid Carcinoma
In this multicentric retrospective observational study, we investigated the potential risk factors for radioiodine (RAI) indication and the post-treatment recurrence of intermediate-risk differentiated thyroid cancer (DTC) 1 and 3 years from diagnosis. We included 121 patients who underwent thyroidectomy for intermediate-risk DTC. The 92 patients (76.0%) who underwent RAI treatment had a higher prevalence of extra-thyroid micro-extension (mETE) (p = 0.03), pT3 staging (p = 0.03) and recourse to therapeutic central (p = 0.04) and lateral (p = 0.01) neck dissection, as well as higher numbers (p = 0.02) and greater dimensions (p = 0.01) of lymph node metastases, compared with untreated patients. Relapse was observed in 18.1% and 20.7% of cases 1 and 3 years from diagnosis, respectively, with no significant differences between groups. A lower age at diagnosis (p = 0.03) and higher levels of stimulated thyroglobulin (Tg) (p = 0.04) emerged as the only independent risk factors for tumour relapse at 1 year. Tumour relapse at 3 years was only independently predicted by the presence of tumour relapse at 1 year (p = 0.04). In conclusion, mETE, pT3 and the presence of large, multiple or clinically evident lymph node metastases represent the main indicators for referring patients to RAI treatment. Early recurrence may be considered the most relevant factor when planning further surveillance.
- 29 April 2023
- Published by MDPI AG in Journal of Personalized Medicine
- Vol. 13 (5) , 775
Open AccessPost-Surgical Indications to Radioiodine Treatment and Potential Risk Factors for Post-Treatment Recurrence in Patients with Intermediate-Risk Differentiated Thyroid Carcinoma
In this multicentric retrospective observational study, we investigated the potential risk factors for radioiodine (RAI) indication and the post-treatment recurrence of intermediate-risk differentiated thyroid cancer (DTC) 1 and 3 years from diagnosis. We included 121 patients who underwent thyroidectomy for intermediate-risk DTC. The 92 patients (76.0%) who underwent RAI treatment had a higher prevalence of extra-thyroid micro-extension (mETE) (p = 0.03), pT3 staging (p = 0.03) and recourse to therapeutic central (p = 0.04) and lateral (p = 0.01) neck dissection, as well as higher numbers (p = 0.02) and greater dimensions (p = 0.01) of lymph node metastases, compared with untreated patients. Relapse was observed in 18.1% and 20.7% of cases 1 and 3 years from diagnosis, respectively, with no significant differences between groups. A lower age at diagnosis (p = 0.03) and higher levels of stimulated thyroglobulin (Tg) (p = 0.04) emerged as the only independent risk factors for tumour relapse at 1 year. Tumour relapse at 3 years was only independently predicted by the presence of tumour relapse at 1 year (p = 0.04). In conclusion, mETE, pT3 and the presence of large, multiple or clinically evident lymph node metastases represent the main indicators for referring patients to RAI treatment. Early recurrence may be considered the most relevant factor when planning further surveillance.
- Open Access
- 1 July 2021
- Published by MDPI AG in Endocrines
- Vol. 2 (3) , 171-184
Endocrine Disorders in Autoimmune Rheumatological Diseases: A Focus on Thyroid Autoimmune Diseases and on the Effects of Chronic Glucocorticoid Treatment
Autoimmune rheumatological diseases’ incidence and prevalence have risen over the last decades and they are becoming increasingly important worldwide. Thyroid autoimmune diseases share with them an imbalance in the immune system that lead to a pro-inflammatory environment. Usually this is the result of a multi-factorial process. In fact, it includes not only a possible genetic predisposition, but also environmental causes like microbiota dysbiosis, diet rich in processed foods, exposure to toxicants and infections. However, many aspects are currently under study. This paper aims to examine the factors that participate in the developing of rheumatological and thyroid autoimmune diseases. Moreover, as glucocorticoids still represent a leading treatment for systemic autoimmune rheumatological diseases, our secondary aim is to summarize the main effects of glucocorticoids treatment focusing on iatrogenic Cushing’s syndrome and glucocorticoids’ withdrawal syndrome.
- 1 July 2021
- Published by MDPI AG in Endocrines
- Vol. 2 (3) , 171-184
Open AccessEndocrine Disorders in Autoimmune Rheumatological Diseases: A Focus on Thyroid Autoimmune Diseases and on the Effects of Chronic Glucocorticoid Treatment
Autoimmune rheumatological diseases’ incidence and prevalence have risen over the last decades and they are becoming increasingly important worldwide. Thyroid autoimmune diseases share with them an imbalance in the immune system that lead to a pro-inflammatory environment. Usually this is the result of a multi-factorial process. In fact, it includes not only a possible genetic predisposition, but also environmental causes like microbiota dysbiosis, diet rich in processed foods, exposure to toxicants and infections. However, many aspects are currently under study. This paper aims to examine the factors that participate in the developing of rheumatological and thyroid autoimmune diseases. Moreover, as glucocorticoids still represent a leading treatment for systemic autoimmune rheumatological diseases, our secondary aim is to summarize the main effects of glucocorticoids treatment focusing on iatrogenic Cushing’s syndrome and glucocorticoids’ withdrawal syndrome.
- 12 February 2021
- Published by SAGE Publications in Thyroid®
- Vol. 31 (2) , 264-271
Real-World Performance of the American Thyroid Association Risk Estimates in Predicting 1-Year Differentiated Thyroid Cancer Outcomes: A Prospective Multicenter Study of 2000 Patients
Background: One of the most widely used risk stratification systems for estimating individual patients' risk of persistent or recurrent differentiated thyroid cancer (DTC) is the American Thyroid Association (ATA) guidelines. The 2015 ATA version, which has increased the number of patients considered at low or intermediate risk, has been validated in several retrospective, single-center studies. The aims of this study were to evaluate the real-world performance of the 2015 ATA risk stratification system in predicting the response to treatment 12 months after the initial treatment and to determine the extent to which this performance is affected by the treatment center in which it is used. Methods: A prospective cohort of DTC patients collected by the Italian Thyroid Cancer Observatory web-based database was analyzed. We reviewed all records present in the database and selected consecutive cases that satisfied inclusion criteria: (i) histological diagnosis of DTC, with the exclusion of noninvasive follicular thyroid neoplasm with papillary-like nuclear features; (ii) complete data of the initial treatment and pathological features; and (iii) results of 1-year follow-up visit (6–18 months after the initial treatment), including all data needed to classify the estimated response to treatment. Results: The final cohort was composed of 2071 patients from 40 centers. The ATA risk of persistent/recurrent disease was classified as low in 1109 patients (53.6%), intermediate in 796 (38.4%), and high in 166 (8.0%). Structural incomplete responses were documented in only 86 (4.2%) patients: 1.5% in the low-risk, 5.7% in the intermediate-risk, and 14.5% in the high-risk group. The baseline ATA risk class proved to be a significant predictor of structural persistent disease, both for intermediate-risk (odds ratio [OR] 4.67; 95% confidence interval [CI] 2.59–8.43) and high-risk groups (OR 16.48; CI 7.87–34.5). Individual center did not significantly influence the prediction of the 1-year disease status. Conclusions: The ATA risk stratification system is a reliable predictor of short-term outcomes in patients with DTC in real-world clinical settings characterized by center heterogeneity in terms of size, location, level of care, local management strategies, and resource availability.
- 12 February 2021
- Published by SAGE Publications in Thyroid®
- Vol. 31 (2) , 264-271
Real-World Performance of the American Thyroid Association Risk Estimates in Predicting 1-Year Differentiated Thyroid Cancer Outcomes: A Prospective Multicenter Study of 2000 Patients
Background: One of the most widely used risk stratification systems for estimating individual patients' risk of persistent or recurrent differentiated thyroid cancer (DTC) is the American Thyroid Association (ATA) guidelines. The 2015 ATA version, which has increased the number of patients considered at low or intermediate risk, has been validated in several retrospective, single-center studies. The aims of this study were to evaluate the real-world performance of the 2015 ATA risk stratification system in predicting the response to treatment 12 months after the initial treatment and to determine the extent to which this performance is affected by the treatment center in which it is used. Methods: A prospective cohort of DTC patients collected by the Italian Thyroid Cancer Observatory web-based database was analyzed. We reviewed all records present in the database and selected consecutive cases that satisfied inclusion criteria: (i) histological diagnosis of DTC, with the exclusion of noninvasive follicular thyroid neoplasm with papillary-like nuclear features; (ii) complete data of the initial treatment and pathological features; and (iii) results of 1-year follow-up visit (6–18 months after the initial treatment), including all data needed to classify the estimated response to treatment. Results: The final cohort was composed of 2071 patients from 40 centers. The ATA risk of persistent/recurrent disease was classified as low in 1109 patients (53.6%), intermediate in 796 (38.4%), and high in 166 (8.0%). Structural incomplete responses were documented in only 86 (4.2%) patients: 1.5% in the low-risk, 5.7% in the intermediate-risk, and 14.5% in the high-risk group. The baseline ATA risk class proved to be a significant predictor of structural persistent disease, both for intermediate-risk (odds ratio [OR] 4.67; 95% confidence interval [CI] 2.59–8.43) and high-risk groups (OR 16.48; CI 7.87–34.5). Individual center did not significantly influence the prediction of the 1-year disease status. Conclusions: The ATA risk stratification system is a reliable predictor of short-term outcomes in patients with DTC in real-world clinical settings characterized by center heterogeneity in terms of size, location, level of care, local management strategies, and resource availability.
- Open Access
- 1 September 2000
- Published by The Endocrine Society in The Journal of Clinical Endocrinology & Metabolism
- Vol. 85 (9) , 3141-3146
Stimulatory Effect of Adrenocorticotropin on Cortisol, Aldosterone, and Dehydroepiandrosterone Secretion in Normal Humans: Dose-Response Study*
The short ACTH test is widely used in clinical practice for the diagnosis of adrenal insufficiency. It is classically performed administering 250.0 μg ACTH(1–24) although 1.0 μg ACTH dose has been reported having maximal stimulatory effect on cortisol levels in normal subjects. We aimed to define the maximal and the minimal stimulatory ACTH dose on cortisol, aldosterone, and dehydroepiandrosterone (DHEA) in humans. To this goal, in 12 normal volunteers (6 males and 6 females; age, 22–34 yr; body mass index 20–25 kg/m2; body surface 1.6–1.9 m2), we studied the dose-response effect of eight ACTH doses (0.01, 0.03, 0.06, 0.125, 0.5, 1.0, 25.0, and 250.0 μg) on cortisol, aldosterone, and DHEA levels. Each ACTH dose administered at 0 min was followed by a second ACTH dose of 250.0 μg at +60 min. The cortisol Δ areas under response curve (ΔAUCs) after all ACTH doses, apart from 0.01 μg, were significantly higher (P < 0.02) than that after placebo, showing a clear dose-response relationship (P< 0.001). The doses of 0.03 and 1.0 μg ACTH were the minimal and maximal effective doses, respectively. The cortisol response to 250.0μ g ACTH was not modified by pretreatment with 0.01, 0.03, and 0.06μ g ACTH doses, whereas it was progressively reduced by increasing the dose of ACTH pretreatment (P < 0.001). The aldosteroneΔ AUCs to all but 0.01 μg ACTH doses were significantly higher (P < 0.02) than that after placebo, showing a clear dose-response relationship (P < 0.001). The dose of 0.03 μg was the minimal effective stimulating dose, whereas 25.0 μg showed the same aldosterone-releasing effect of 250.0 μg. The aldosterone response to 250.0 μg ACTH, preceeded by placebo, was not modified by pretreatment with 0.01 and 0.03 μg ACTH doses, whereas it was reduced by increasing the dose of ACTH pretreatment (P < 0.05–0.02). The DHEA ΔAUCs to all ACTH doses were significantly higher (P < 0.01) than that after placebo, showing a clear dose-response relationship (P< 0.001). The doses of 0.01 and 1.0 μg ACTH were the minimal and maximal effective dose, respectively. The DHEA response to 250.0 μg ACTH was not modified by pretreatment with 0.01, 0.03, 0.06, and 0.125μ g ACTH doses, whereas it was progressively reduced by pretreatment with 0.5, 1.0, and 25.0 μg ACTH doses (P < 0.01). In conclusion, these results show that an extremely low ACTH dose is needed to stimulate adrenal steroids and, among them, DHEA seems the most sensitive to corticotropin stimulation.
- 1 September 2000
- Published by The Endocrine Society in The Journal of Clinical Endocrinology & Metabolism
- Vol. 85 (9) , 3141-3146
Open AccessStimulatory Effect of Adrenocorticotropin on Cortisol, Aldosterone, and Dehydroepiandrosterone Secretion in Normal Humans: Dose-Response Study*
The short ACTH test is widely used in clinical practice for the diagnosis of adrenal insufficiency. It is classically performed administering 250.0 μg ACTH(1–24) although 1.0 μg ACTH dose has been reported having maximal stimulatory effect on cortisol levels in normal subjects. We aimed to define the maximal and the minimal stimulatory ACTH dose on cortisol, aldosterone, and dehydroepiandrosterone (DHEA) in humans. To this goal, in 12 normal volunteers (6 males and 6 females; age, 22–34 yr; body mass index 20–25 kg/m2; body surface 1.6–1.9 m2), we studied the dose-response effect of eight ACTH doses (0.01, 0.03, 0.06, 0.125, 0.5, 1.0, 25.0, and 250.0 μg) on cortisol, aldosterone, and DHEA levels. Each ACTH dose administered at 0 min was followed by a second ACTH dose of 250.0 μg at +60 min. The cortisol Δ areas under response curve (ΔAUCs) after all ACTH doses, apart from 0.01 μg, were significantly higher (P < 0.02) than that after placebo, showing a clear dose-response relationship (P< 0.001). The doses of 0.03 and 1.0 μg ACTH were the minimal and maximal effective doses, respectively. The cortisol response to 250.0μ g ACTH was not modified by pretreatment with 0.01, 0.03, and 0.06μ g ACTH doses, whereas it was progressively reduced by increasing the dose of ACTH pretreatment (P < 0.001). The aldosteroneΔ AUCs to all but 0.01 μg ACTH doses were significantly higher (P < 0.02) than that after placebo, showing a clear dose-response relationship (P < 0.001). The dose of 0.03 μg was the minimal effective stimulating dose, whereas 25.0 μg showed the same aldosterone-releasing effect of 250.0 μg. The aldosterone response to 250.0 μg ACTH, preceeded by placebo, was not modified by pretreatment with 0.01 and 0.03 μg ACTH doses, whereas it was reduced by increasing the dose of ACTH pretreatment (P < 0.05–0.02). The DHEA ΔAUCs to all ACTH doses were significantly higher (P < 0.01) than that after placebo, showing a clear dose-response relationship (P< 0.001). The doses of 0.01 and 1.0 μg ACTH were the minimal and maximal effective dose, respectively. The DHEA response to 250.0 μg ACTH was not modified by pretreatment with 0.01, 0.03, 0.06, and 0.125μ g ACTH doses, whereas it was progressively reduced by pretreatment with 0.5, 1.0, and 25.0 μg ACTH doses (P < 0.01). In conclusion, these results show that an extremely low ACTH dose is needed to stimulate adrenal steroids and, among them, DHEA seems the most sensitive to corticotropin stimulation.