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FENOPROFEN AND FREE TRIIODOTHYRONINE MEASUREMENT
101 FENOPROFEN AND FREE TRIIODOTHYRONINE MEASUREMENT
LUTEINISING-HORMONE-RELEASING HORMONE AND CRYPTORCHIDISM
SIR,-Non-steroidal anti-inflammatory drugs can hamper the interpretation of thyroid-function tests.1-3 We report here our findings with fenoprofen. A patient referred for monitoring of L-thyroxine therapy had a very high free triiodothyronine (FT 3) level of 34 pmol/1 (normal 3-0-8-1) as measured by the ’Amerlex-M’ kit (Amersham International). The thyrotropin level of 6-0 mU/1 (IRMA method, Serono Diagnostics) more accurately reflected the clinical thyroid status. This patient was taking fenoprofen. Normal human serum and FT3-free serum spiked with a small amount of fenoprofen showed increased FT3 levels, as did
SIR,-Your editorial on the role of LHRH in the treatment of cryptorchidism (May 17, p 1133) maintains that intranasal LHRH is "not easily justified as the initial treatment in the management of undescended testes". This conclusion was based in large part on the results of the randomised study of de Muinck Keiser-Schrama and colleagues.1 The Dutch trial shows, however, that two 4-week courses of intranasal LHRH produced a 51% rate of descent for testes that were either at the scrotal entrance or high in the scrotum (see table, constructed from their fig 1). The success rate for testes at the inguinal ring or higher is low (see table), but avoiding operation TESTICULAR DESCENT TO SCROTUM IN RELATION TO INITIAL
from two volunteers who took one to three 300 mg tablets (see table). TSH and free thyroxine (amerlex-M method), remained unchanged. serum
POSITION
STUDIES OF FENOPROFEN INTERFERENCE WITH THYROID FUNCTION TESTS
*
Most caudal position after two LHRH 15 "vanishing testes".
courses.
t Includes
*Blood taken 3 h after last tablet.
The chemical structure offenoprofen (2-(3-phenoxyphenyl) propionic acid) resembles that of T (3,5,3’-triiodothyronine):
Chemical structures.
Upper: fenoprofen. triiodothyronine.
Lower:
Our evidence suggests that fenoprofen cross-reacts with the antibody used in amerlex-M assay for measuring FT3’ producing erroneously high values. We thank Mr A. C. McGill, Newcastle General results.
Hospital, for the FT,,
Departments of Biochemistry and Medicine, North Tees General Hospital, Stockton on Tees, Cleveland TS19 8PE
HEATHER M. THORNES DAVID CARR
1. Ratcliffe WA, Hazleton RA, Thomson JA, Ratcliffe JG. The effect of fencloflenac on thyroid function tests in vivo and in vitro. Clin Endocrinol 1980; 13: 569. 2. Fowler PD, Crook PR, Hothersall TE. Diclofenac Na and thyroid function tests.
in half of the remaining cases would appear to at least warrant further serious consideration of LHRH in these less severe cases. We have shown that age at orchidopexy does not appear to influence risk of testicular cancer even if done at a very young age.23 There is also little evidence to support the view that age at orchidopexy influences the risk of infertility :2there is only one adequate follow-up study" that suggests that the later the age at operation the worse the subsequent sperm count, and the totality of evidence suggests that, at least after the boy’s second birthday, orchidopexy has little effect on fertility. Histological studies5 do, however, suggest that operating before age 2 and preferably before age 1, may prevent some damage to the germinal epithelium of the testis and preserve subsequent fertility, although there are no adequate follow-up data to support this view. We would suggest that any future trials of LHRH in cases under age 2 should be confmed to testes at the scrotal entrance or high in the scrotum. The Dutch study resultsl suggest that two 4-week courses of intranasal LHRH (with a 4 week break between courses) achieves twice the success rate of a single course. Any future randomised clinical trial of intranasal LHRH needs therefore to continue for at least two courses of treatment. The detailed anatomical findings at orchidopexy reported by the Dutch investigators strongly suggest that cryptorchid testes positioned in the inguinal canal or abdomen are almost all blocked from descending as are most cryptorchid testes at the inguinal ring, and these testes appear most unlikely to respond even to pulsatile LHRH by injection. A precise description of the clinical findings before operation in the 12 cases in which inguinal ring testes descended with intranasal LHRH may help one to decide on the small subset of such cases that may be worth including in any new randomised study. Division of Epidemiology, Institute of Cancer Research,
Sutton, Surrey ICRF Epidemiology Unit, Radcliffe Infirmary, Oxford
Ramey JN, Burrow GN, Spalding SW, Donabedian RK, Speroff L, Frantz AG. The effect of aspirin and indomethacin on the TRH response in man. J Clin Endocrinol Metab 1975; 43: 107-14.
M. C. PIKE
1. de Muinck Keizer-Schrama SMPF, Hazebroek FWJ, Matroos AW, Drop SLS, Molenaar JC, Visser HKA. Double-blind, placebo-controlled study of luteinisinghormone-releasing-hormone nasal spray in treatment of undescended testes. Lancet 1986; i: 876-80. 2. Pike MC, Chilvers C, Peckham MJ. Effect of age at orchidopexy on nsk of testicular cancer Lancet 1986, i: 1246-48. 3. Chilvers C, Dudley NE, Gough MH, Jackson MB, Pike MC. Undescended testis: the effect of treatment on subsequent risk of subfertility and malignancy. J Pediatr Surg 4.
Rheumatoid Rehabil 1982; 21: 2-7. 3.
CLAIR CHILVERS
M. B. JACKSON
(in press). Ludwig G, Potempa J. Der optimale zeitpunkt der behandlung des kryptorchismus. Dtsch Med Wochenschr 1975; 100: 680-83.
5.
Mengel W, Wronecki K, Zimmerman FA. Companson of the morphology of normal and cryptorchid testes. In: Fonkalsrud EW, Mengel W, eds. The undescended testis. London Year Book, 1981: 57-74.
LUTEINISING-HORMONE-RELEASING HORMONE AND CRYPTORCHIDISM
SIR,-Non-steroidal anti-inflammatory drugs can hamper the interpretation of thyroid-function tests.1-3 We report here our findings with fenoprofen. A patient referred for monitoring of L-thyroxine therapy had a very high free triiodothyronine (FT 3) level of 34 pmol/1 (normal 3-0-8-1) as measured by the ’Amerlex-M’ kit (Amersham International). The thyrotropin level of 6-0 mU/1 (IRMA method, Serono Diagnostics) more accurately reflected the clinical thyroid status. This patient was taking fenoprofen. Normal human serum and FT3-free serum spiked with a small amount of fenoprofen showed increased FT3 levels, as did
SIR,-Your editorial on the role of LHRH in the treatment of cryptorchidism (May 17, p 1133) maintains that intranasal LHRH is "not easily justified as the initial treatment in the management of undescended testes". This conclusion was based in large part on the results of the randomised study of de Muinck Keiser-Schrama and colleagues.1 The Dutch trial shows, however, that two 4-week courses of intranasal LHRH produced a 51% rate of descent for testes that were either at the scrotal entrance or high in the scrotum (see table, constructed from their fig 1). The success rate for testes at the inguinal ring or higher is low (see table), but avoiding operation TESTICULAR DESCENT TO SCROTUM IN RELATION TO INITIAL
from two volunteers who took one to three 300 mg tablets (see table). TSH and free thyroxine (amerlex-M method), remained unchanged. serum
POSITION
STUDIES OF FENOPROFEN INTERFERENCE WITH THYROID FUNCTION TESTS
*
Most caudal position after two LHRH 15 "vanishing testes".
courses.
t Includes
*Blood taken 3 h after last tablet.
The chemical structure offenoprofen (2-(3-phenoxyphenyl) propionic acid) resembles that of T (3,5,3’-triiodothyronine):
Chemical structures.
Upper: fenoprofen. triiodothyronine.
Lower:
Our evidence suggests that fenoprofen cross-reacts with the antibody used in amerlex-M assay for measuring FT3’ producing erroneously high values. We thank Mr A. C. McGill, Newcastle General results.
Hospital, for the FT,,
Departments of Biochemistry and Medicine, North Tees General Hospital, Stockton on Tees, Cleveland TS19 8PE
HEATHER M. THORNES DAVID CARR
1. Ratcliffe WA, Hazleton RA, Thomson JA, Ratcliffe JG. The effect of fencloflenac on thyroid function tests in vivo and in vitro. Clin Endocrinol 1980; 13: 569. 2. Fowler PD, Crook PR, Hothersall TE. Diclofenac Na and thyroid function tests.
in half of the remaining cases would appear to at least warrant further serious consideration of LHRH in these less severe cases. We have shown that age at orchidopexy does not appear to influence risk of testicular cancer even if done at a very young age.23 There is also little evidence to support the view that age at orchidopexy influences the risk of infertility :2there is only one adequate follow-up study" that suggests that the later the age at operation the worse the subsequent sperm count, and the totality of evidence suggests that, at least after the boy’s second birthday, orchidopexy has little effect on fertility. Histological studies5 do, however, suggest that operating before age 2 and preferably before age 1, may prevent some damage to the germinal epithelium of the testis and preserve subsequent fertility, although there are no adequate follow-up data to support this view. We would suggest that any future trials of LHRH in cases under age 2 should be confmed to testes at the scrotal entrance or high in the scrotum. The Dutch study resultsl suggest that two 4-week courses of intranasal LHRH (with a 4 week break between courses) achieves twice the success rate of a single course. Any future randomised clinical trial of intranasal LHRH needs therefore to continue for at least two courses of treatment. The detailed anatomical findings at orchidopexy reported by the Dutch investigators strongly suggest that cryptorchid testes positioned in the inguinal canal or abdomen are almost all blocked from descending as are most cryptorchid testes at the inguinal ring, and these testes appear most unlikely to respond even to pulsatile LHRH by injection. A precise description of the clinical findings before operation in the 12 cases in which inguinal ring testes descended with intranasal LHRH may help one to decide on the small subset of such cases that may be worth including in any new randomised study. Division of Epidemiology, Institute of Cancer Research,
Sutton, Surrey ICRF Epidemiology Unit, Radcliffe Infirmary, Oxford
Ramey JN, Burrow GN, Spalding SW, Donabedian RK, Speroff L, Frantz AG. The effect of aspirin and indomethacin on the TRH response in man. J Clin Endocrinol Metab 1975; 43: 107-14.
M. C. PIKE
1. de Muinck Keizer-Schrama SMPF, Hazebroek FWJ, Matroos AW, Drop SLS, Molenaar JC, Visser HKA. Double-blind, placebo-controlled study of luteinisinghormone-releasing-hormone nasal spray in treatment of undescended testes. Lancet 1986; i: 876-80. 2. Pike MC, Chilvers C, Peckham MJ. Effect of age at orchidopexy on nsk of testicular cancer Lancet 1986, i: 1246-48. 3. Chilvers C, Dudley NE, Gough MH, Jackson MB, Pike MC. Undescended testis: the effect of treatment on subsequent risk of subfertility and malignancy. J Pediatr Surg 4.
Rheumatoid Rehabil 1982; 21: 2-7. 3.
CLAIR CHILVERS
M. B. JACKSON
(in press). Ludwig G, Potempa J. Der optimale zeitpunkt der behandlung des kryptorchismus. Dtsch Med Wochenschr 1975; 100: 680-83.
5.
Mengel W, Wronecki K, Zimmerman FA. Companson of the morphology of normal and cryptorchid testes. In: Fonkalsrud EW, Mengel W, eds. The undescended testis. London Year Book, 1981: 57-74.