The Effect of Intravenous Prostaglandin F 2a on Serum Luteinizing Hormone, Follicle-Stimulating Hormone and Plasma Cortisol in Normal Men DR. GILLIAN M. CRAIG Clinical Investigation Unit, Dudley Road Hospital, Birmingham, B18 7QH England ABSTRACT. Prostaglandin F 2Q (PGF 2 J was given intravenously in a maximum dose of 24 fig per min to 6 normal male volunteers. There was no change in serum luteinizing hormone, follicle-stimulating
P
ROSTAGLANDIN F 2a (PGF2a) or prostaglandin F l a (PGF la ) given intravenously or intraventricularly, does not alter plasma luteinizing hormone (LH) in female rats (1), whereas injections of prostaglandin E2 (PGE2), prostaglandin E1 (PGEJ (1) or dopamine (2) into the third ventricle increase plasma LH. However intravenous PGF 2a increases pituitary LH content in female rats, without evidence of decreased LH release (3), and in ewes, intracarotid infusions of PGF 2a in doses of 6.0 /xg/h or more, increase plasma LH (4). In one study in men, plasma LH fell during PGF 2a infusion, and during a control period on saline (5). In rats in vivo, PGE 2 but not prostaglandin A, or PGF 2a appears to stimulate ACTH release (6). However in rat adrenal in vitro, PGEj, PGE2 and PGF 2a cause an increase in steroidogenesis, the effect being less sustained than that of ACTH (7). Transient elevation of plasma cortisol has been reported in men given intravenous PGF 2a (5) but a stress effect could not be excluded. This study was undertaken to determine whether intravenous PGF 2a influenced serum LH, follicle-stimulating hormone (FSH) or plasma cortisol in normal men.
Materials and Methods The project was undertaken with the approval of the ethical committee of Dudley Road Hospital, Birmingham, and with the consent of the Committee on Safety in Medicines. Intravenous PGF 2 Q was given to 6 normal male volunteers of age range 24 to 45 yr, with their informed consent. The subjects varied in weight from 47 kg to 102 kg. All were on a normal diet and no drugs. Fasting was not requested, but subReceived August 26, 1974.
hormone, or blood glucose. Plasma cortisol fluctuated but no sustained rise was demonstrated. (/ Clin Endocrinol Metab 41: 180, 1975)
jects 2 and 6 did so voluntarily on the morning of the study. The subjects, with one exception, were doctors. They rested on a bed throughout the study. Control venous blood samples were taken for LH, FSH, plasma cortisol and blood glucose at 9 AM and again at 10 AM after a 1-h infusion of 100 ml of normal saline. Thereafter PGF 2 Q in normal saline was given for 3 h at the following increasing rates, by means of a Palmer pump: 3.0 /xg/min for 30 min, 6.0 /xg/min for 30 min, 12.0 fig/min for 1 h and 24 /xg/min for 1 h. Blood samples were taken hourly by intermittent venepuncture, during the PGF 2a infusion. Serum for LH and FSH was kept at 4 C overnight, and delivered to the laboratory the following day. Pulse, blood pressure and temperature were monitored. A total of 2430 fxg of PGF2oi in 162 ml of normal saline was given during the 3-h test period, and 100 ml of normal saline was infused during the 1-h control period. Serum LH and FSH were measured by a double antibody radioimmunoassay employing reagents described by Shaw et al. (8). Results are expressed in units per liter, all units being given in terms of the human pituitary FSH and LH reference preparation MRC 69/104 obtained from the Division of Biological Standards, National Institute for Medical Research, Mill Hill, London NW7 1AA. MRC 69/104 is derived from the National Pituitary Agency preparation LER907 and has been assigned a potency of 10 IU FSH and 25 IU LH per ampoule (9). Plasma cortisol was measured by the method of Mattingly (10) and blood glucose by an AutoAnalyzer technique (11).
Results There were no unpleasant side effects. In Case 3, of weight 56 kg, body temperature rose to 37.4 C during the highest infusion rate of PGF 2a and he developed some edema of the forearm. There were no significant changes in pulse or blood pressure. Some subjects developed erythema of the forearm vein receiving the infusion.
180
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181
COMMENTS There was no change in serum LH, FSH or blood glucose (Table 1). Serum LH did not rise above control values during PGF 2a infusion in 4 out of 6 subjects. In Case 1, serum LH values of 4 and 5 U/liter were obtained during PGF 2a infusion, compared with control values of 3 U/liter. In Case 2, the serum LH rose above control values during infusion of 12 /u,g/min but returned to control levels during infusion of 24 /u,g/min of PGF 2a . The serum FSH rose above control values only in Case 3 after 24 /ug/min of PGF 2a . In contrast in Case 1, the serum FSH was lower after 24 /xg/min of PGF 2a than at any other time. There was some fluctuation in plasma cortisol values during the study. The 9 AM control specimens gave the highest value, as would be expected from the normal diurnal rhythm, or from apprehension engendered by insertion of an intravenous cannula (12). When the 10 AM control value was compared with the mean plasma cortisol during PGF 2a infusion for each individual, using a Student's t test, the changes were not significant (Table 2).
Discussion The study demonstrated that intravenous PGF 2a does not cause significant, sustained change in plasma cortisol levels. This suggests that in humans, as in rats (6) PGF 2a does not increase ACTH release. Nevertheless, there were marked fluctuations in the plasma cortisol levels. Although intermittent venepuncture may have caused a rise in plasma cortisol in some individuals (12), it is not possible to exclude the possibility that PGF 2a may have some transient effect on adrenal steroidogenesis in man, as in rats in vitro (7). Blood glucose did not alter, hence the changes in plasma cortisol were not due to hypoglycemia. TABLE
1. Mean results of serum LH, FSH and blood glucose Serum LH Serum FSH U/liter (MRC 69/104) Mean ± lSD
9 AM control 10 AM control 11AMPGF!O
12 AM PGF2o 1 PM PGF2Q
2.8 2.6 2.5 2.5 2.8
dt dt dt dt dt
1.34 1.03 1.12 1.12 1.67
Mean ± 1 SD 2.5 ± 2.5 ± 2.3 ± 2.5 ± 2.8 ±
0.95 0.76 1.01 0.95 1.36
Blood glucose mg/100 ml Mean 59 59 61 62 62
T A B L E 2. Individual plasma cortisol results (/xg/100 ml; PGF 2o
Control
Case Case Case Case Case Case
1 2 3 4 5 6
Mean ± 1 SD
9 AM
1 0 AM
11 AM
12 noon
1 PM
**
*.
**
**
..
22.5 22.2 * 26.0 20.4
16.4 17.8 10.2 16.0 15.0
11.0 22.5 * 21.0 11.2
14.7 13.2 6.6 11.5 14.8
12.2 21.4
22.9 ± 1.77
15.1 ± 2.73
16.4 ±5.35
12.2 ±3.03
17.6 ±5.36
•
20.5 17.6
PGF 2a
12.6 19.0 6.6 17.7 14.3 14.04 NS1
* Insufficient blood for measurement. ** Not requested. t Individual 10 AM control values were compared with mean plasma cortisol for each case during treatment with PGF 2o . Applying a Student's t test the results were not significant. {t = 0.90).
Serum LH and FSH levels were not affected by PGF 2a . This confirms the work of Coudert and Faiman (5) for FSH, but in their study LH levels fell during PGF 2a infusion and during the control period on saline. Changes in LH in individual subjects fell within the range reported to occur spontaneously in day time in normal men (13). The lack of effect on FSH was particularly surprising since the PGF 2a was given in a regime virtually identical to that used by Gillespie, Brummer and Chard (14) who demonstrated a rise in oxytocin levels in normal men during PGF 2a or to a lesser extent PGE2 infusions. Synthetic oxytocin given intravenously increases FSH but not LH in young men (15). The intravenous route is an inefficient way of giving prostaglandins in an attempt to influence pituitary function as 95 to 99% of prostaglandins, except PGA! and PGA2 (16) are removed in one passage through the lungs (17). In women, only 3% of labeled PGF 2a is detectable in the blood W2 min after intravenous injection (18). However, the reported release of oxytocin during PGF 2a infusion in men (14) must indicate that PGE2 and PGF 2a given intravenously can directly influence pituitary function in men, unless the oxytocin was released from an organ other than the pituitary, or was released as an indirect effect of prostaglandins proximal to the lungs. The physiological triggers for prostaglandin release at hypothalamic level are uncertain. However prostaglandins have a modulating role on autonomic transmission (19,20), and a scheme linking dopamine, nor-adrenaline and prostaglandins with LH release has been suggested (21). The failure of intravenous PGF 2a to increase LH or FSH levels in men, suggests that that
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182
COMMENTS
postulated dopamine-noradrenaline-prostaglandin pathway for LH release may be applicable only to PGE2 or PGEj. It may be relevant that in male rats the plasma LH response to intraventricular dopamine is relatively small (2), and that prostaglandins of the F series are released in much smaller quantities than PGE compounds on nerve stimulation (20). Studies with intravenous PGE 2 in humans are in progress. PGF 2a can facilitate liberation of nor-adrenaline (20) and preliminary observations made during the present study suggest that PGF 2a increases urinary metanephrine output in normal men. Further work is needed to establish this point. Acknowledgments Thanks are due to the volunteers and the staff of the Biochemistry Department of Dudley Road Hospital, Birmingham, England. Serum LH and FSH were measured by Mr. John Williams of the Department of Clinical Endocrinology, the Birmingham and Midland Hospital for Women, by courtesy of Dr. W. Butt. PGF2a was supplied by Dr. Hinchley of Upjohn Limited, Crawley, Sussex. References 1. Harms, P. C , S. R. Ojeda, and S. M. McCann, Endocrinology 94: 1459, 1974. 2. Schneider, H. P. G., and S. M. McCann, Endocrinology 86: 1127. 1970. 3. Labhsetwar, A. P. J Reprod Fertil 23: 155. 1970. 4. Carlson, J. C , B. Barcikowski, and J. A. McCracken, J Reprod Fertil 34: 357, 1973.
JCE & M • 1975 Vol 41 • No 1
5. Coudert, S. P., and C. Faiman, Prostaglandins 3: 89, 1973. 6. Peng, T. C , K. M. Six, and P. L. Munson, Endocrinology 86: 202, 1972. 7. Flack, J. D., R. Jessup, and P. W. Ramwell, Science 163: 691, 1969. 8. Shaw, R. W., W. R. Butt, D. R. London, and J. C. Marshall, / Ohstet Gynaecol Br Commonw 81: 632, 1974. 9. Bangham, D. R., I. Berryrnan, H. Burger, P. M. Cotes, B. E. Furnival, W. M. Hunter, A. R. Midgley, M. V. Mussett, L. E. Reichart, E. Rosemberg, R. J. Ryan, and L. Wide, / Clin Endocrinol Metab 36: 647, 1973. 10. Mattingly, D.,y Clin Pathol 15: 374, 1962. 11. Trinder, P., Ann Clin Biochem 6: 24, 1969. 12. Cjarny, D., V. H. T. James, J. Landon, and F. C. Greenwood, Lancet II: 126, 1968. 13. Nankin, H. R., and P. Troen, / Clin Endocrinol Metab 33: 558, 1971. 14. Gillespie, A., H. C. Brummer, and T. Chard, Br Med J 1: 534, 1972. 15. Legros, J. J., and P. Franchimont, Lancet 2: 735, 1968. 16. McGiff, J. C , N. A. Terragno, J. C. Strand, J. B. Lee, A. J. Lonigro, and K. K. F. Ng, Nature 223: 742, 1964. 17. Ferreira, S. H., and J. R. Vane, Nature (Lond) 216: 868, 1967. 18. Granstrom, E., In Bergstrom, S. (ed.), Prostaglandins in Fertility Control, W. H. O., Stockholm, 1972, p. 12. 19. Hedqvist, P., Ada Physiol Scand (Suppl. 345) 1970. 20. Brody, M. J., Population Report: Prostaglandins. Series G. Number 3. December 1973, Department of Medical and Public Affairs, The George Washington University Medical Center, 2001 S. Street, N.W. Washington D.C. 20009. 21. Craig, G. M., Postgrad Med J 51: 74, 1975.
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P
ROSTAGLANDIN F 2a (PGF2a) or prostaglandin F l a (PGF la ) given intravenously or intraventricularly, does not alter plasma luteinizing hormone (LH) in female rats (1), whereas injections of prostaglandin E2 (PGE2), prostaglandin E1 (PGEJ (1) or dopamine (2) into the third ventricle increase plasma LH. However intravenous PGF 2a increases pituitary LH content in female rats, without evidence of decreased LH release (3), and in ewes, intracarotid infusions of PGF 2a in doses of 6.0 /xg/h or more, increase plasma LH (4). In one study in men, plasma LH fell during PGF 2a infusion, and during a control period on saline (5). In rats in vivo, PGE 2 but not prostaglandin A, or PGF 2a appears to stimulate ACTH release (6). However in rat adrenal in vitro, PGEj, PGE2 and PGF 2a cause an increase in steroidogenesis, the effect being less sustained than that of ACTH (7). Transient elevation of plasma cortisol has been reported in men given intravenous PGF 2a (5) but a stress effect could not be excluded. This study was undertaken to determine whether intravenous PGF 2a influenced serum LH, follicle-stimulating hormone (FSH) or plasma cortisol in normal men.
Materials and Methods The project was undertaken with the approval of the ethical committee of Dudley Road Hospital, Birmingham, and with the consent of the Committee on Safety in Medicines. Intravenous PGF 2 Q was given to 6 normal male volunteers of age range 24 to 45 yr, with their informed consent. The subjects varied in weight from 47 kg to 102 kg. All were on a normal diet and no drugs. Fasting was not requested, but subReceived August 26, 1974.
hormone, or blood glucose. Plasma cortisol fluctuated but no sustained rise was demonstrated. (/ Clin Endocrinol Metab 41: 180, 1975)
jects 2 and 6 did so voluntarily on the morning of the study. The subjects, with one exception, were doctors. They rested on a bed throughout the study. Control venous blood samples were taken for LH, FSH, plasma cortisol and blood glucose at 9 AM and again at 10 AM after a 1-h infusion of 100 ml of normal saline. Thereafter PGF 2 Q in normal saline was given for 3 h at the following increasing rates, by means of a Palmer pump: 3.0 /xg/min for 30 min, 6.0 /xg/min for 30 min, 12.0 fig/min for 1 h and 24 /xg/min for 1 h. Blood samples were taken hourly by intermittent venepuncture, during the PGF 2a infusion. Serum for LH and FSH was kept at 4 C overnight, and delivered to the laboratory the following day. Pulse, blood pressure and temperature were monitored. A total of 2430 fxg of PGF2oi in 162 ml of normal saline was given during the 3-h test period, and 100 ml of normal saline was infused during the 1-h control period. Serum LH and FSH were measured by a double antibody radioimmunoassay employing reagents described by Shaw et al. (8). Results are expressed in units per liter, all units being given in terms of the human pituitary FSH and LH reference preparation MRC 69/104 obtained from the Division of Biological Standards, National Institute for Medical Research, Mill Hill, London NW7 1AA. MRC 69/104 is derived from the National Pituitary Agency preparation LER907 and has been assigned a potency of 10 IU FSH and 25 IU LH per ampoule (9). Plasma cortisol was measured by the method of Mattingly (10) and blood glucose by an AutoAnalyzer technique (11).
Results There were no unpleasant side effects. In Case 3, of weight 56 kg, body temperature rose to 37.4 C during the highest infusion rate of PGF 2a and he developed some edema of the forearm. There were no significant changes in pulse or blood pressure. Some subjects developed erythema of the forearm vein receiving the infusion.
180
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181
COMMENTS There was no change in serum LH, FSH or blood glucose (Table 1). Serum LH did not rise above control values during PGF 2a infusion in 4 out of 6 subjects. In Case 1, serum LH values of 4 and 5 U/liter were obtained during PGF 2a infusion, compared with control values of 3 U/liter. In Case 2, the serum LH rose above control values during infusion of 12 /u,g/min but returned to control levels during infusion of 24 /u,g/min of PGF 2a . The serum FSH rose above control values only in Case 3 after 24 /ug/min of PGF 2a . In contrast in Case 1, the serum FSH was lower after 24 /xg/min of PGF 2a than at any other time. There was some fluctuation in plasma cortisol values during the study. The 9 AM control specimens gave the highest value, as would be expected from the normal diurnal rhythm, or from apprehension engendered by insertion of an intravenous cannula (12). When the 10 AM control value was compared with the mean plasma cortisol during PGF 2a infusion for each individual, using a Student's t test, the changes were not significant (Table 2).
Discussion The study demonstrated that intravenous PGF 2a does not cause significant, sustained change in plasma cortisol levels. This suggests that in humans, as in rats (6) PGF 2a does not increase ACTH release. Nevertheless, there were marked fluctuations in the plasma cortisol levels. Although intermittent venepuncture may have caused a rise in plasma cortisol in some individuals (12), it is not possible to exclude the possibility that PGF 2a may have some transient effect on adrenal steroidogenesis in man, as in rats in vitro (7). Blood glucose did not alter, hence the changes in plasma cortisol were not due to hypoglycemia. TABLE
1. Mean results of serum LH, FSH and blood glucose Serum LH Serum FSH U/liter (MRC 69/104) Mean ± lSD
9 AM control 10 AM control 11AMPGF!O
12 AM PGF2o 1 PM PGF2Q
2.8 2.6 2.5 2.5 2.8
dt dt dt dt dt
1.34 1.03 1.12 1.12 1.67
Mean ± 1 SD 2.5 ± 2.5 ± 2.3 ± 2.5 ± 2.8 ±
0.95 0.76 1.01 0.95 1.36
Blood glucose mg/100 ml Mean 59 59 61 62 62
T A B L E 2. Individual plasma cortisol results (/xg/100 ml; PGF 2o
Control
Case Case Case Case Case Case
1 2 3 4 5 6
Mean ± 1 SD
9 AM
1 0 AM
11 AM
12 noon
1 PM
**
*.
**
**
..
22.5 22.2 * 26.0 20.4
16.4 17.8 10.2 16.0 15.0
11.0 22.5 * 21.0 11.2
14.7 13.2 6.6 11.5 14.8
12.2 21.4
22.9 ± 1.77
15.1 ± 2.73
16.4 ±5.35
12.2 ±3.03
17.6 ±5.36
•
20.5 17.6
PGF 2a
12.6 19.0 6.6 17.7 14.3 14.04 NS1
* Insufficient blood for measurement. ** Not requested. t Individual 10 AM control values were compared with mean plasma cortisol for each case during treatment with PGF 2o . Applying a Student's t test the results were not significant. {t = 0.90).
Serum LH and FSH levels were not affected by PGF 2a . This confirms the work of Coudert and Faiman (5) for FSH, but in their study LH levels fell during PGF 2a infusion and during the control period on saline. Changes in LH in individual subjects fell within the range reported to occur spontaneously in day time in normal men (13). The lack of effect on FSH was particularly surprising since the PGF 2a was given in a regime virtually identical to that used by Gillespie, Brummer and Chard (14) who demonstrated a rise in oxytocin levels in normal men during PGF 2a or to a lesser extent PGE2 infusions. Synthetic oxytocin given intravenously increases FSH but not LH in young men (15). The intravenous route is an inefficient way of giving prostaglandins in an attempt to influence pituitary function as 95 to 99% of prostaglandins, except PGA! and PGA2 (16) are removed in one passage through the lungs (17). In women, only 3% of labeled PGF 2a is detectable in the blood W2 min after intravenous injection (18). However, the reported release of oxytocin during PGF 2a infusion in men (14) must indicate that PGE2 and PGF 2a given intravenously can directly influence pituitary function in men, unless the oxytocin was released from an organ other than the pituitary, or was released as an indirect effect of prostaglandins proximal to the lungs. The physiological triggers for prostaglandin release at hypothalamic level are uncertain. However prostaglandins have a modulating role on autonomic transmission (19,20), and a scheme linking dopamine, nor-adrenaline and prostaglandins with LH release has been suggested (21). The failure of intravenous PGF 2a to increase LH or FSH levels in men, suggests that that
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182
COMMENTS
postulated dopamine-noradrenaline-prostaglandin pathway for LH release may be applicable only to PGE2 or PGEj. It may be relevant that in male rats the plasma LH response to intraventricular dopamine is relatively small (2), and that prostaglandins of the F series are released in much smaller quantities than PGE compounds on nerve stimulation (20). Studies with intravenous PGE 2 in humans are in progress. PGF 2a can facilitate liberation of nor-adrenaline (20) and preliminary observations made during the present study suggest that PGF 2a increases urinary metanephrine output in normal men. Further work is needed to establish this point. Acknowledgments Thanks are due to the volunteers and the staff of the Biochemistry Department of Dudley Road Hospital, Birmingham, England. Serum LH and FSH were measured by Mr. John Williams of the Department of Clinical Endocrinology, the Birmingham and Midland Hospital for Women, by courtesy of Dr. W. Butt. PGF2a was supplied by Dr. Hinchley of Upjohn Limited, Crawley, Sussex. References 1. Harms, P. C , S. R. Ojeda, and S. M. McCann, Endocrinology 94: 1459, 1974. 2. Schneider, H. P. G., and S. M. McCann, Endocrinology 86: 1127. 1970. 3. Labhsetwar, A. P. J Reprod Fertil 23: 155. 1970. 4. Carlson, J. C , B. Barcikowski, and J. A. McCracken, J Reprod Fertil 34: 357, 1973.
JCE & M • 1975 Vol 41 • No 1
5. Coudert, S. P., and C. Faiman, Prostaglandins 3: 89, 1973. 6. Peng, T. C , K. M. Six, and P. L. Munson, Endocrinology 86: 202, 1972. 7. Flack, J. D., R. Jessup, and P. W. Ramwell, Science 163: 691, 1969. 8. Shaw, R. W., W. R. Butt, D. R. London, and J. C. Marshall, / Ohstet Gynaecol Br Commonw 81: 632, 1974. 9. Bangham, D. R., I. Berryrnan, H. Burger, P. M. Cotes, B. E. Furnival, W. M. Hunter, A. R. Midgley, M. V. Mussett, L. E. Reichart, E. Rosemberg, R. J. Ryan, and L. Wide, / Clin Endocrinol Metab 36: 647, 1973. 10. Mattingly, D.,y Clin Pathol 15: 374, 1962. 11. Trinder, P., Ann Clin Biochem 6: 24, 1969. 12. Cjarny, D., V. H. T. James, J. Landon, and F. C. Greenwood, Lancet II: 126, 1968. 13. Nankin, H. R., and P. Troen, / Clin Endocrinol Metab 33: 558, 1971. 14. Gillespie, A., H. C. Brummer, and T. Chard, Br Med J 1: 534, 1972. 15. Legros, J. J., and P. Franchimont, Lancet 2: 735, 1968. 16. McGiff, J. C , N. A. Terragno, J. C. Strand, J. B. Lee, A. J. Lonigro, and K. K. F. Ng, Nature 223: 742, 1964. 17. Ferreira, S. H., and J. R. Vane, Nature (Lond) 216: 868, 1967. 18. Granstrom, E., In Bergstrom, S. (ed.), Prostaglandins in Fertility Control, W. H. O., Stockholm, 1972, p. 12. 19. Hedqvist, P., Ada Physiol Scand (Suppl. 345) 1970. 20. Brody, M. J., Population Report: Prostaglandins. Series G. Number 3. December 1973, Department of Medical and Public Affairs, The George Washington University Medical Center, 2001 S. Street, N.W. Washington D.C. 20009. 21. Craig, G. M., Postgrad Med J 51: 74, 1975.
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