Istituto di Patologia Speciale Medica e Metodologia Clinica I Facolt5 di Medicina, Universit5 di Napoli
A COMPARATIVE STUDY OF METABOLIC AND H O R M O N A L RESPONSES TO SOMATOSTATIN AND PROPRANOLOL IN MAN DARfO GIUGLIANO
ROBERTOTORELLA
SAVERIOSGAMBATO
Somatostatin, previously thought to have no intrinsic effects on glucose 4 and lipid: metabolism in man. has recently been reported to potentiate the lipolysis induced by orciprenaline", a selective I£agonist. Since the augmented FFA levels following somatostatin administration are believed to be a consequence of insulin inhibition 4, in the present study we compared the metabolic effects of somatostatin and propranolol, a drug known to decrease basal insulin concentrations J0 in order to ascertain whether the somatostatin-induced increase in FFA levels is merely a consequence of lack of insulin. MATERIALS AND METHODS Informed consent was obtained from 18 healthy, non obese, medical student volunteers, aged 22-31 years, after a full explanation of the nature, purpose and possible risks involved in the study. They were free from acute or chronic illness at the time of the study arid had no family history of diabetes. After an over-night fast (12 h) and with the subjects supine, indwelling teflon catheters were inserted in each antecubital vein, one for infusion, the other for blood sampling. Patency was assured by a slow saline (0.9%) drip. After a 30-rain rest, cyclic somatostatin ISerono, Italy), diIuted in 60 ml of saline, was infused in 6 subjects (3 male and 3 female) at the constant rate of 4 !.tg/min, over a period of 60 rain. Six additional subjects (3 male and 3 female), received propranolol (Inderal. I.C.I.) at the constant rate of 0.08 rag/rain for 60 rain. Controt studies with saline were also performed in the remaining 6 subjects. Venous blood specimens were drawn in the basal state (-20 rain), immediately before (0-time) and 15, 30, 45, 60 and 80 min after the start of the infusion. Kcy-v_'ords: FFA,. Glucagon; Gh,cose; Gro*od) bor,eo,e, Insuli:~; Propra~olol, .5o:,v~,!osta:i:.,. Rece{ved: June 10, I978. Acra diaber, fat. 16, 77, 1979. 77
METABOLIC EFFECTS OF SOMATOSTATIN AND PROPRANOLOL
The blood was at once placed in prechilled tubes each containing 1.2 mg of EDTA and 500 U of Trasylol per ml of blood, centrifuged at 4"C and the plasma frozen until the time of analysis not more than 4 weeks later. Plasma glucose was determined according to HU¢OETT and NlXON s, plasma FFA according to DUCOMBE t and plasma glucagon according to LrYcKx s using Unger's 30 K antiserum (BiodataSerono, Italy) which is considered specific for pancreatic glucagon. Plasma insulin was also determined by radioimmunoassay using charcoal dextran for the separation of bound from free hormone (Dow-Lepetit) and plasma growth hormone by a double antibody radioimmunoassay (Dow-Lepetit). Statistical analysis of the results was performed by using Student's paired and unpaired t-test H Results are presented as ~ ---+ SEM. RESULTS As shown in fig. 1, propranolol significantly decreased glucagon levels from a mean basal value of 72 +- 8 pg/ml to a nadir of 59 = 5 pg/ml at 15 rain (p
A COMPARATIVE STUDY OF METABOLIC AND H O R M O N A L RESPONSES TO SOMATOSTATIN AND PROPRANOLOL IN MAN DARfO GIUGLIANO
ROBERTOTORELLA
SAVERIOSGAMBATO
Somatostatin, previously thought to have no intrinsic effects on glucose 4 and lipid: metabolism in man. has recently been reported to potentiate the lipolysis induced by orciprenaline", a selective I£agonist. Since the augmented FFA levels following somatostatin administration are believed to be a consequence of insulin inhibition 4, in the present study we compared the metabolic effects of somatostatin and propranolol, a drug known to decrease basal insulin concentrations J0 in order to ascertain whether the somatostatin-induced increase in FFA levels is merely a consequence of lack of insulin. MATERIALS AND METHODS Informed consent was obtained from 18 healthy, non obese, medical student volunteers, aged 22-31 years, after a full explanation of the nature, purpose and possible risks involved in the study. They were free from acute or chronic illness at the time of the study arid had no family history of diabetes. After an over-night fast (12 h) and with the subjects supine, indwelling teflon catheters were inserted in each antecubital vein, one for infusion, the other for blood sampling. Patency was assured by a slow saline (0.9%) drip. After a 30-rain rest, cyclic somatostatin ISerono, Italy), diIuted in 60 ml of saline, was infused in 6 subjects (3 male and 3 female) at the constant rate of 4 !.tg/min, over a period of 60 rain. Six additional subjects (3 male and 3 female), received propranolol (Inderal. I.C.I.) at the constant rate of 0.08 rag/rain for 60 rain. Controt studies with saline were also performed in the remaining 6 subjects. Venous blood specimens were drawn in the basal state (-20 rain), immediately before (0-time) and 15, 30, 45, 60 and 80 min after the start of the infusion. Kcy-v_'ords: FFA,. Glucagon; Gh,cose; Gro*od) bor,eo,e, Insuli:~; Propra~olol, .5o:,v~,!osta:i:.,. Rece{ved: June 10, I978. Acra diaber, fat. 16, 77, 1979. 77
METABOLIC EFFECTS OF SOMATOSTATIN AND PROPRANOLOL
The blood was at once placed in prechilled tubes each containing 1.2 mg of EDTA and 500 U of Trasylol per ml of blood, centrifuged at 4"C and the plasma frozen until the time of analysis not more than 4 weeks later. Plasma glucose was determined according to HU¢OETT and NlXON s, plasma FFA according to DUCOMBE t and plasma glucagon according to LrYcKx s using Unger's 30 K antiserum (BiodataSerono, Italy) which is considered specific for pancreatic glucagon. Plasma insulin was also determined by radioimmunoassay using charcoal dextran for the separation of bound from free hormone (Dow-Lepetit) and plasma growth hormone by a double antibody radioimmunoassay (Dow-Lepetit). Statistical analysis of the results was performed by using Student's paired and unpaired t-test H Results are presented as ~ ---+ SEM. RESULTS As shown in fig. 1, propranolol significantly decreased glucagon levels from a mean basal value of 72 +- 8 pg/ml to a nadir of 59 = 5 pg/ml at 15 rain (p
