Psychoneuroendocrinology,Vol. 16, No. 6, pp. 499-504, 1991
0306-4530/91 $3.00+0.00 ©1992 Pergamon Press plc
Printed in Great Britain
INFLUENCE OF NALOXONE INFUSION O N PROLACTIN A N D GROWTH HORMONE RESPONSE TO GROWTH HORMONERELEASING HORMONE IN ANOREXIA NERVOSA L. DE MARINIS, A. MANCINI, C. D'AMICO, P. ZuPPI, A. TOFANI, S. DELLA CASA, A. SAPOROSI, P. SAMBO, C. FIUMARA, F. CALABRO, and A. BARBARINO Institute of Endocrinology,the Catholic University School of Medicine, Rome, Italy (Received 6 September 1988; in final form 24 December 1990)
SUMMARY Anorexia nervosa (AN) is frequently associated with anomalies of growth hormone (GH) and prolactin (PRL) secretion. We studied the GH and PRL responses to GHRH1_44 (50 ~g Iv) and the effect of a naloxone infusion (1.6 mg/hr), started 1 hr before GHRH administration, on this response in 12 female patients with AN, aged 15-30 yr, and in seven normal women, aged 19-27 yr, during the follicular phase as controls. In AN, GHRH induced an increase in GH levels similar to that observed in normal subjects. A significant inhibition of the GH response to GHRH was observed during naloxone infusion, similar to the inhibition in normal female subjects during the follicular phase. PRL levels showed a significant increment after GHRH alone and a slight, nonsignificant, PRL increment after GHRH during naloxone infusion in AN patients. In contrast a slight PRL decrease was observed after GHRH, both before and during naloxone infusion, in the normal subjects. Our study demonstrates that endogenous opioids play a role in influencing PRL secretion in patients with AN different from their role in normal subjects.
INTRODUCTION IN PATIENTSWITH ANOREXIANERVOSA(AN), malnutrition is secondary to a psychogenic disturbance of eating. Evidence for an opioid peptide (OP) involvement in the modulation of feeding behaviour has been shown in animals and in humans (Morley, 1987). Several investigators have attempted to elucidate the possible role of OP in the pathogenesis of AN and the potential role of OP antagonists in the treatment of the opposite condition, bulimia (Mitchell et al., 1986). In a preliminary investigation, [~-endorphin (BEP) levels were moderately reduced in patients with AN, and the BEP and ACTH responses to CRF were significantly blunted (Cavagnini et al., 1986). Since BEP is clearly involved in the regulation of pituitary hormone secretion, having a stimulatory effect on GH release in animals and humans (Morley, 1981) and on PRL release in animals (Krieger, 1985), we investigated the effect of a naloxone (NAL) infusion on the PRL Address correspondence and reprint requests to: Dr. L. De Marinis, Institute of Endocrinology, The Catholic University, School of Medicine, Largo A. Gemelli 8, 1-00168, Rome, ITALY. 499
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and G H responses to G H R H in patients with AN and in normal female subjects, in order to further elucidate the endogenous OP tone in this condition. SUBJECTS AND METHODS Twelve patients with AN, ages 15-30 yr, and seven normal female volunteers, ages 19-27 yr, participated in this study. The diagnosis of AN was made with the DSM-III criteria of the American Psychiatric Association (1980). The history of AN lasted from 1-3 yr, five patients had previously participated in physical exercise, and three had suffered some form of family distress before the onset of the symptoms. All patients exhibited a marked food refusal, with an estimated caloric intake ranging from 700-1200 KCal. Five patients presented vomiting behaviour, and two had an excessive use of diuretics or laxatives. Their weight was 30-40% lower than their ideal body weight, and all had amenorrhea. All patients were studied when their weight was stable. They were not taking any medications. The following tests were performed: GHRH test: Following an overnight fast, at 0900h, all patients were placed at bed rest, with an indwelling venous cannula inserted in one arm and maintained open by a saline infusion. GHRH (Bachem, Switzerland) was administered as a bolus of 50 gg Iv at time 0. Blood samples were collected at -15, 0, 15, 30, 60, and 90 min. The mean values of the -15 and 0 min determinations were considered as basal levels. NAL + GHRH test: Following an overnight fast, the same test was repeated during the infusion of NAL (Narcan, Crinos, Italy), 1.6 mg/hr starting 1 hr before GHRH administration (time 0). Blood samples were collected at -60, -30, 0, 15, 30, 60, and 90 min. Time 0 values were considered as basal levels for the evaluation of GHRH effects. Saline test: Two milliliters of normal saline were administered in all patients, and blood was collected at the same intervals as after GHRH administration. The overnight fasting was well accepted by the patients, since it corresponded to their customary eating pattern. The tests were performed in random order, with an interval of at least three days between studies. As a control, GHRH, NAL + GHRH and saline tests were performed in seven normal women, tested during the follicular phase of their menstrual cycle. The three tests, in random order, were performed in the same phase of consecutive menstrual cycles. Blood samples were centrifuged within 2 hr after collection and plasma aliquots frozen at -20°C until assayed. GH and PRL were assayed, with a RIA procedure, with reagents furnished by Biodata, Milan, Italy. Normal ranges in our laboratory are: GH, 0 - 1 0 ng/ml and PRL, 5 - 2 0 ng/ml. Intra- and interassay coefficients of variation were 2.5% and 5.8% for GH and 2.1% and 4.6% for PRL, respectively. The cross reactivity of PRL with GH in our assay was negligible (0.13%). Other hormones also were determined in AN patients (T3, T4, TSH, FSH and LH after GnRH, cortisol, and 17-13-estradiol) by RIA. Normal ranges are indicated in Table III. Statistical analysis was performed with analysis of variance. RESULTS The results of G H R H a d m i n i s t r a t i o n , during N A L or saline i n f u s i o n , on G H levels are reported in Table I. G H R H elicited a G H response in the A N patients c o m p a r a b l e to that observed in the normal subjects, with a peak response at 30 m i n and a return to basal levels by 90 min. At the starting of NAL infusion (time -60), mean (+ SEM) G H levels were 8.4 + 2.7 n g / m l in the a n o r e c t i c p a t i e n t s a n d 1 5 . 1 + 6.7 n g / m l i n the n o r m a l s u b j e c t s . T h e y were n o t significantly modified by the 1-hr NAL infusion. NAL infusion completely blunted the G H response to GHRH, with a significant difference at 15, 30, 60 m i n in c o m p a r i s o n with the a d m i n i s t r a t i o n of G H R H alone, s i m i l a r l y in the anorectic and the normal women. The PRL response to GHRH, NAL + GHRH, and saline in the anorectic patients is shown in
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NALOXONEANDPRL ANDGH RESPONSETOGHRFI IN ANOREXIANERVOSA
Table II. Basal PRL levels and peak responses are shown in the figure. GH1LH induced a significant PRL 14 increase when administered alone; the mean % peak in- ~" 12 10 crease was 247.3+45.5%. During the NAL infusion, the PRL response to GHRH was blunted: slight, non- #: significant, PRL increase was still present; the mean % peak increase was 140.6 + 9.2 (p < 0.05 vs. % peak after 0 BP BP BP BP GHRH alone). During saline infusion, a slight, nonGRF NAL+GRF GRF NAL+GRF significant, PRL decrease was observed (Table II); NORMALWOMEN ANORECTICWOMEN mean nadir values were 7 9 . 4 + 5 . 6 % of basal values Mean (± SEM} basal PRL levels and peak (i.e., a decrease of 20.5%) (p < 0.05 vs. % variation responses to GHRH alone or GHRH adafter NAL + GHRH, andp
0306-4530/91 $3.00+0.00 ©1992 Pergamon Press plc
Printed in Great Britain
INFLUENCE OF NALOXONE INFUSION O N PROLACTIN A N D GROWTH HORMONE RESPONSE TO GROWTH HORMONERELEASING HORMONE IN ANOREXIA NERVOSA L. DE MARINIS, A. MANCINI, C. D'AMICO, P. ZuPPI, A. TOFANI, S. DELLA CASA, A. SAPOROSI, P. SAMBO, C. FIUMARA, F. CALABRO, and A. BARBARINO Institute of Endocrinology,the Catholic University School of Medicine, Rome, Italy (Received 6 September 1988; in final form 24 December 1990)
SUMMARY Anorexia nervosa (AN) is frequently associated with anomalies of growth hormone (GH) and prolactin (PRL) secretion. We studied the GH and PRL responses to GHRH1_44 (50 ~g Iv) and the effect of a naloxone infusion (1.6 mg/hr), started 1 hr before GHRH administration, on this response in 12 female patients with AN, aged 15-30 yr, and in seven normal women, aged 19-27 yr, during the follicular phase as controls. In AN, GHRH induced an increase in GH levels similar to that observed in normal subjects. A significant inhibition of the GH response to GHRH was observed during naloxone infusion, similar to the inhibition in normal female subjects during the follicular phase. PRL levels showed a significant increment after GHRH alone and a slight, nonsignificant, PRL increment after GHRH during naloxone infusion in AN patients. In contrast a slight PRL decrease was observed after GHRH, both before and during naloxone infusion, in the normal subjects. Our study demonstrates that endogenous opioids play a role in influencing PRL secretion in patients with AN different from their role in normal subjects.
INTRODUCTION IN PATIENTSWITH ANOREXIANERVOSA(AN), malnutrition is secondary to a psychogenic disturbance of eating. Evidence for an opioid peptide (OP) involvement in the modulation of feeding behaviour has been shown in animals and in humans (Morley, 1987). Several investigators have attempted to elucidate the possible role of OP in the pathogenesis of AN and the potential role of OP antagonists in the treatment of the opposite condition, bulimia (Mitchell et al., 1986). In a preliminary investigation, [~-endorphin (BEP) levels were moderately reduced in patients with AN, and the BEP and ACTH responses to CRF were significantly blunted (Cavagnini et al., 1986). Since BEP is clearly involved in the regulation of pituitary hormone secretion, having a stimulatory effect on GH release in animals and humans (Morley, 1981) and on PRL release in animals (Krieger, 1985), we investigated the effect of a naloxone (NAL) infusion on the PRL Address correspondence and reprint requests to: Dr. L. De Marinis, Institute of Endocrinology, The Catholic University, School of Medicine, Largo A. Gemelli 8, 1-00168, Rome, ITALY. 499
500
L. DEMARINISet al.
and G H responses to G H R H in patients with AN and in normal female subjects, in order to further elucidate the endogenous OP tone in this condition. SUBJECTS AND METHODS Twelve patients with AN, ages 15-30 yr, and seven normal female volunteers, ages 19-27 yr, participated in this study. The diagnosis of AN was made with the DSM-III criteria of the American Psychiatric Association (1980). The history of AN lasted from 1-3 yr, five patients had previously participated in physical exercise, and three had suffered some form of family distress before the onset of the symptoms. All patients exhibited a marked food refusal, with an estimated caloric intake ranging from 700-1200 KCal. Five patients presented vomiting behaviour, and two had an excessive use of diuretics or laxatives. Their weight was 30-40% lower than their ideal body weight, and all had amenorrhea. All patients were studied when their weight was stable. They were not taking any medications. The following tests were performed: GHRH test: Following an overnight fast, at 0900h, all patients were placed at bed rest, with an indwelling venous cannula inserted in one arm and maintained open by a saline infusion. GHRH (Bachem, Switzerland) was administered as a bolus of 50 gg Iv at time 0. Blood samples were collected at -15, 0, 15, 30, 60, and 90 min. The mean values of the -15 and 0 min determinations were considered as basal levels. NAL + GHRH test: Following an overnight fast, the same test was repeated during the infusion of NAL (Narcan, Crinos, Italy), 1.6 mg/hr starting 1 hr before GHRH administration (time 0). Blood samples were collected at -60, -30, 0, 15, 30, 60, and 90 min. Time 0 values were considered as basal levels for the evaluation of GHRH effects. Saline test: Two milliliters of normal saline were administered in all patients, and blood was collected at the same intervals as after GHRH administration. The overnight fasting was well accepted by the patients, since it corresponded to their customary eating pattern. The tests were performed in random order, with an interval of at least three days between studies. As a control, GHRH, NAL + GHRH and saline tests were performed in seven normal women, tested during the follicular phase of their menstrual cycle. The three tests, in random order, were performed in the same phase of consecutive menstrual cycles. Blood samples were centrifuged within 2 hr after collection and plasma aliquots frozen at -20°C until assayed. GH and PRL were assayed, with a RIA procedure, with reagents furnished by Biodata, Milan, Italy. Normal ranges in our laboratory are: GH, 0 - 1 0 ng/ml and PRL, 5 - 2 0 ng/ml. Intra- and interassay coefficients of variation were 2.5% and 5.8% for GH and 2.1% and 4.6% for PRL, respectively. The cross reactivity of PRL with GH in our assay was negligible (0.13%). Other hormones also were determined in AN patients (T3, T4, TSH, FSH and LH after GnRH, cortisol, and 17-13-estradiol) by RIA. Normal ranges are indicated in Table III. Statistical analysis was performed with analysis of variance. RESULTS The results of G H R H a d m i n i s t r a t i o n , during N A L or saline i n f u s i o n , on G H levels are reported in Table I. G H R H elicited a G H response in the A N patients c o m p a r a b l e to that observed in the normal subjects, with a peak response at 30 m i n and a return to basal levels by 90 min. At the starting of NAL infusion (time -60), mean (+ SEM) G H levels were 8.4 + 2.7 n g / m l in the a n o r e c t i c p a t i e n t s a n d 1 5 . 1 + 6.7 n g / m l i n the n o r m a l s u b j e c t s . T h e y were n o t significantly modified by the 1-hr NAL infusion. NAL infusion completely blunted the G H response to GHRH, with a significant difference at 15, 30, 60 m i n in c o m p a r i s o n with the a d m i n i s t r a t i o n of G H R H alone, s i m i l a r l y in the anorectic and the normal women. The PRL response to GHRH, NAL + GHRH, and saline in the anorectic patients is shown in
501
NALOXONEANDPRL ANDGH RESPONSETOGHRFI IN ANOREXIANERVOSA
Table II. Basal PRL levels and peak responses are shown in the figure. GH1LH induced a significant PRL 14 increase when administered alone; the mean % peak in- ~" 12 10 crease was 247.3+45.5%. During the NAL infusion, the PRL response to GHRH was blunted: slight, non- #: significant, PRL increase was still present; the mean % peak increase was 140.6 + 9.2 (p < 0.05 vs. % peak after 0 BP BP BP BP GHRH alone). During saline infusion, a slight, nonGRF NAL+GRF GRF NAL+GRF significant, PRL decrease was observed (Table II); NORMALWOMEN ANORECTICWOMEN mean nadir values were 7 9 . 4 + 5 . 6 % of basal values Mean (± SEM} basal PRL levels and peak (i.e., a decrease of 20.5%) (p < 0.05 vs. % variation responses to GHRH alone or GHRH adafter NAL + GHRH, andp
