Original Paper
Neuroendocrinoiogy 1992;56:459-463
Vittorio Coiro° Luigi Caprettf Riccardo Volpia Camillo DavoliJ Antonio Marcato1' Umberto Cavazzinia Giovanni Caffarrif Giuseppe RossŸ Paolo Chioderah
Stimulation of ACTH/Cortisol by Intravenously Infused Substance P in Normal Men: Inhibition by Sodium Valproate
University Clinics of a Internal Medicine, b Endocrinology, School of Medicine, University of Parma, c Endocrine Unit, Hospital of Codogno, d Division of Internal Medicine, Hospital of Cremona, ' Division of Internal Medicine, Hospital of Fiorenzuola, and r Biochemistry Laboratory, Hospital of Guastalla, Italy
Abstract The effect of synthetic substance P (SP), infused intravenously in doses of 0.5, 1 or 1.5 pm ol/kg^/m in-1 over 60 min on ACTH/cortisoI secretion was evaluated in 7 healthy men. SP tests and a control test with normal saline were randomly performed at weekly intervals. During tests, SP infusion did not produce untoward side effects or changes in blood pressure. Plasma ACTH and cortisol levels were not modified when normal saline or the lowest dose of SP were infused, whereas they were significantly increased in a dose-depen dent fashion when higher amounts of SP were administered. Further studies were performed in another 7 healthy men to test the possible influence of GABAergic neurotransmission on the ACTH/cortisoI response to SP. For this purpose, subjects were tested with SP (1.5 pmol/kg_l/m in_l) alone and on a different occasion with SP after pretreatment with the GABAergic agent sodium valproate (200 mg 16, 8 and 1 h before the SP test). Again, the admin istration of SP induced a significant increase in plasma ACTH and cortisol levels. The pretreatment with sodium valproate completely abolished both ACTH and cortisol responses to SP. These data demonstrate for the first time in humans that the systemic infusion of SP stimulates ACTH/cortisoI secre tion, suggesting the involvement of a GABAergic mechanism in the regulation of the action of SP.
Received: September 24. 1991 Accepted after revision: January 31, 1992
Vittorio Coiro, MD Cattedra di Clínica Medica Generale c Terapia Medica Universitá di Parma ViaGramsci 14 1-43100 Parma (Italy)
© 1992 S. Karger AG, Basel 0028-3835/92/0564-0459 S 2.75/0
Downloaded by: Stockholm University Library 130.237.165.40 - 4/24/2018 2:29:57 PM
Key Words Sodium valproate Substance P ACTH Cortisol
Materials and Methods Seven healthy men, aged 26-35 years, participated in the study. The subjects were informed of the purpose of the study and gave their informed consent. The study was in accordance with the Hel sinki II declaration. All men were in good health, without clinical and laboratory evidence of hepatic, renal, heart or other organic dis ease. All subjects were within 10% of their ideal body weight. None of them was a smoker or was addicted to an excessive alcohol con sumption ( < 300 ml ethanol/week). Subjects were not taking any drug before and during the study. The subjects were tested three times with SP alone at different doses and once with normal saline (NaCI 0.9%). The tests were carried out double blind, in random order, at weekly intervals. S P Infusion Tests
Experiments started at 09.00 h. Two intravenous catheters were placed into antecubital veins of both arms of the subjects lying in the recumbent position after an overnight fast and rest in bed. One catheter was used for SP or saline infusion, the other served for blood sampling. Synthetic SP (Clinalfa, Laufelfingen, Switzerland) was infused intravenously over a period of 60 min at doses of 0.5, 1.0 or 1.5 pmol/kg~l/min~l. The calculated dose was dissolved in 50 ml isotonic saline containing 87 pmol human serum albumin
460
(Istituto Sierovaccinogeno ltaliano, Santantimo, Italy) per liter. Blood samples were collected 10 min (time -10) and just before (time 0) SP infusion. Further blood specimens were withdrawn at time 10, 20, 30, 40, 50, 60, 70 and 80 min. S a lin e Infusion Test
The test was performed as previously described, except for the administration of an equal volume of normal saline (plus human serum albumin) instead of SP solution. In an additional study, the effect ofSPwas examined in the pres ence of the GABAergic agent sodium valproate. Seven healthy men (aged 28-36 years), in the same clinical and experimental condi tions described in the previous study, were tested with SP alone or after treatment with sodium valproate. Tests were carried out in ran dom order at weekly intervals. S P plus S odium Valproate Test
Sodium valproate (Depakin; Signia-Tau, Rome, Italy) was given by mouth in three doses of 200 mg each at 8-hour intervals, starting at 16.00 h of the day preceding the experimental day. The SP test was performed as described above with the infusion of 1.5 pmol/ kg^/m in '1 SP. Control S P Test
This test was performed as previously described; a placebo was given instead of sodium valproate. All blood samples were used for measurements of ACTH and cortisol. Plasma ACTH [10] and cortisol [II] were measured with specific RIA methods. The limits of detection of the ACTH and cor tisol assays were 10.0 pg/ml and 0.6 ug/dl, respectively. The intra assay coefficients of variation were 7 .1% for ACTH and 4.0% for cortisol. The interassay coefficients of variation were 9.9% for ACTH and 7.0% for cortisol. Mean blood pressure and heart rate were monitored at each sampling time during all tests. Statistical analysis was performed with Wilcoxon’s matched pair rank sum test and analysis of variance (ANOVA) followed by Scheffe's multiple contrast test. Data are reported as means ± SE.
Results
SP Infusion Study Saline Infusion Test. Plasma ACTH and cortisol levels did not change significantly during saline infusion (fig. 1). SP Infusion Tests. The administration of the lowest dose (0.5 pmol/kg^'/min"1) of SP was unable to change the circulating concentrations of ACTH (NS vs. saline test; fig. la). Significant dose-dependent increments in plasma ACTH concentrations were observed when higher amounts of SP were infused (1.0 pmol/kg^'/mm-1 SP: p
Neuroendocrinoiogy 1992;56:459-463
Vittorio Coiro° Luigi Caprettf Riccardo Volpia Camillo DavoliJ Antonio Marcato1' Umberto Cavazzinia Giovanni Caffarrif Giuseppe RossŸ Paolo Chioderah
Stimulation of ACTH/Cortisol by Intravenously Infused Substance P in Normal Men: Inhibition by Sodium Valproate
University Clinics of a Internal Medicine, b Endocrinology, School of Medicine, University of Parma, c Endocrine Unit, Hospital of Codogno, d Division of Internal Medicine, Hospital of Cremona, ' Division of Internal Medicine, Hospital of Fiorenzuola, and r Biochemistry Laboratory, Hospital of Guastalla, Italy
Abstract The effect of synthetic substance P (SP), infused intravenously in doses of 0.5, 1 or 1.5 pm ol/kg^/m in-1 over 60 min on ACTH/cortisoI secretion was evaluated in 7 healthy men. SP tests and a control test with normal saline were randomly performed at weekly intervals. During tests, SP infusion did not produce untoward side effects or changes in blood pressure. Plasma ACTH and cortisol levels were not modified when normal saline or the lowest dose of SP were infused, whereas they were significantly increased in a dose-depen dent fashion when higher amounts of SP were administered. Further studies were performed in another 7 healthy men to test the possible influence of GABAergic neurotransmission on the ACTH/cortisoI response to SP. For this purpose, subjects were tested with SP (1.5 pmol/kg_l/m in_l) alone and on a different occasion with SP after pretreatment with the GABAergic agent sodium valproate (200 mg 16, 8 and 1 h before the SP test). Again, the admin istration of SP induced a significant increase in plasma ACTH and cortisol levels. The pretreatment with sodium valproate completely abolished both ACTH and cortisol responses to SP. These data demonstrate for the first time in humans that the systemic infusion of SP stimulates ACTH/cortisoI secre tion, suggesting the involvement of a GABAergic mechanism in the regulation of the action of SP.
Received: September 24. 1991 Accepted after revision: January 31, 1992
Vittorio Coiro, MD Cattedra di Clínica Medica Generale c Terapia Medica Universitá di Parma ViaGramsci 14 1-43100 Parma (Italy)
© 1992 S. Karger AG, Basel 0028-3835/92/0564-0459 S 2.75/0
Downloaded by: Stockholm University Library 130.237.165.40 - 4/24/2018 2:29:57 PM
Key Words Sodium valproate Substance P ACTH Cortisol
Materials and Methods Seven healthy men, aged 26-35 years, participated in the study. The subjects were informed of the purpose of the study and gave their informed consent. The study was in accordance with the Hel sinki II declaration. All men were in good health, without clinical and laboratory evidence of hepatic, renal, heart or other organic dis ease. All subjects were within 10% of their ideal body weight. None of them was a smoker or was addicted to an excessive alcohol con sumption ( < 300 ml ethanol/week). Subjects were not taking any drug before and during the study. The subjects were tested three times with SP alone at different doses and once with normal saline (NaCI 0.9%). The tests were carried out double blind, in random order, at weekly intervals. S P Infusion Tests
Experiments started at 09.00 h. Two intravenous catheters were placed into antecubital veins of both arms of the subjects lying in the recumbent position after an overnight fast and rest in bed. One catheter was used for SP or saline infusion, the other served for blood sampling. Synthetic SP (Clinalfa, Laufelfingen, Switzerland) was infused intravenously over a period of 60 min at doses of 0.5, 1.0 or 1.5 pmol/kg~l/min~l. The calculated dose was dissolved in 50 ml isotonic saline containing 87 pmol human serum albumin
460
(Istituto Sierovaccinogeno ltaliano, Santantimo, Italy) per liter. Blood samples were collected 10 min (time -10) and just before (time 0) SP infusion. Further blood specimens were withdrawn at time 10, 20, 30, 40, 50, 60, 70 and 80 min. S a lin e Infusion Test
The test was performed as previously described, except for the administration of an equal volume of normal saline (plus human serum albumin) instead of SP solution. In an additional study, the effect ofSPwas examined in the pres ence of the GABAergic agent sodium valproate. Seven healthy men (aged 28-36 years), in the same clinical and experimental condi tions described in the previous study, were tested with SP alone or after treatment with sodium valproate. Tests were carried out in ran dom order at weekly intervals. S P plus S odium Valproate Test
Sodium valproate (Depakin; Signia-Tau, Rome, Italy) was given by mouth in three doses of 200 mg each at 8-hour intervals, starting at 16.00 h of the day preceding the experimental day. The SP test was performed as described above with the infusion of 1.5 pmol/ kg^/m in '1 SP. Control S P Test
This test was performed as previously described; a placebo was given instead of sodium valproate. All blood samples were used for measurements of ACTH and cortisol. Plasma ACTH [10] and cortisol [II] were measured with specific RIA methods. The limits of detection of the ACTH and cor tisol assays were 10.0 pg/ml and 0.6 ug/dl, respectively. The intra assay coefficients of variation were 7 .1% for ACTH and 4.0% for cortisol. The interassay coefficients of variation were 9.9% for ACTH and 7.0% for cortisol. Mean blood pressure and heart rate were monitored at each sampling time during all tests. Statistical analysis was performed with Wilcoxon’s matched pair rank sum test and analysis of variance (ANOVA) followed by Scheffe's multiple contrast test. Data are reported as means ± SE.
Results
SP Infusion Study Saline Infusion Test. Plasma ACTH and cortisol levels did not change significantly during saline infusion (fig. 1). SP Infusion Tests. The administration of the lowest dose (0.5 pmol/kg^'/min"1) of SP was unable to change the circulating concentrations of ACTH (NS vs. saline test; fig. la). Significant dose-dependent increments in plasma ACTH concentrations were observed when higher amounts of SP were infused (1.0 pmol/kg^'/mm-1 SP: p
