Radioimmunoassay of Thyrotropin Releasing Hormone in Plasma and Urine

Saito, Shiro; Musa, K; Yamamoto, Suzuyo; Oshima, Ichiyo; Funato, T

doi:10.1507/endocrj1954.22.303

Cited by 19 publications

(11 citation statements)

References 7 publications

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“…In accordance with the findings of Lom¬ bardi et al (1978a) and Amino et al (1981) for third trimester plasma, we found maternal IR-TRH levels similar to those in non-pregnant euthy¬ roid women, the IR-TRH levels being in the same order of magnitude as those reported for adults in previous studies (Oliver et al 1974;Saito et al 1975;Mitsumaetal. 1976;Lombardi et al 1978b;Andreassen et al 1979) but lower than those found by Guignier et al ( 1981 ) and by Mallik et al ( 1982).…”

Section: Discussionsupporting

confidence: 93%

Immunoreactive thyrotrophin-releasing hormone like material (IR-TRH LM) in human cord blood: high circulating serum levels but possible non-identity with hypothalamic TRH

Kaufman¹,

Elewaut²,

Vermeulen³

1983

Acta Endocrinologica

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Levels of immunoreactive thyrotrophin-releasing hormone like material (IR-TRH LM) were measured in paired maternal and umbilical cord serum samples (n = 45) and in serum of non-pregnant women (n = 63), using a sensitive and specific radioimmunoassay.In all pairs IR-TRH LM in venous cord serum (mean 91.3 pg/ml, range 20\p=n-\270) was markedly elevated as compared to maternal serum (mean 13.5 pg/ml, range 0\p=n-\37, P < 0.001, the maternal levels being similar to those in non-pregnant women (mean 12.0 pg/ml, range 0\p=n-\39, P > 0.1). In 23 cases IR-TRH LM was also measured in arterial cord serum: arterial and venous cord levels were highly significantly correlated (r = 0.904) with higher arterial levels in 22 out of 23 cases (mean 117.8 pg/ml, range 32\p=n-\280 and 90.6 pg/ml, range 20-270, P < 0.001), suggesting that cord IR-TRH LM is not of placental origin. There was no correlation between individual levels of IR-TRH LM and either TSH, T4, T3 or FT4 levels in either maternal or cord serum.Agar gel electrophoresis and equilibrium dialysis of adult and cord serum pre-incubated with [125I]TRH or [3H]TRH revealed no protein binding. Cord IR-TRH LM was immunologically, as well as in paper electrophoresis and in gelfiltration, indistinguishable from synthetic and hypothalamic TRH. In vitro degradation of synthetic TRH was much slower in cord serum as compared to maternal and control serum (P < 0.001). In vitro degradation of cord IR-TRH LM could not be demonstrated, neither by cord serum itself nor by adult serum, this in contrast to hypothalamus extracted TRH which was readily degraded by adult serum. Neither the presence of an inhibiting substance, nor methodological factors seem to account for the apparently different behaviour of cord IR-TRH. It is suggested that circulating IR-TRH could be closely related, but still different from tissue extracted and synthetic TRH. The striking differences in foetal, perinatal and adult thyroid physiology, with drastic changes in hormonal levels occurring in the early postnatal period, are well documented (Fisher et al. 1977;Fisher 1978).A physiologic role of thyrotrophin-releasing hor¬ mone (TRH) in the regulation of foetal and perina¬ tal thyroid function is not yet established. The main purpose of the present study was to gain informa¬ tion on the levels of circulating IR-TRH in neo¬ nates and their possible relation to thyroid func¬ tion. Material and Methods Subjects and samplingproceduresUmbilical cord and maternal blood was collected imme¬ diately after delivery following normal fullterm preg¬ nancy in 45 healthy women. In all subjects paired sam¬ ples were obtained by simultaneous puncture of the umbilical cord vein (UCV) and of the maternal femoral artery (MFA); whenever possible (n = 23) an additional

show abstract

Section: Discussionsupporting

confidence: 93%

Immunoreactive thyrotrophin-releasing hormone like material (IR-TRH LM) in human cord blood: high circulating serum levels but possible non-identity with hypothalamic TRH

Kaufman¹,

Elewaut²,

Vermeulen³

1983

Acta Endocrinologica

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“…The data for crossreactivity of the TRF antiserum produced by us showed that our TRF antiserum was specific to synthetic TRF except for L-Pip3-TRF, compared with the data of Bassiri and Utiger (1972), Visser et al (1974), Mitsuma et al (1974), and Saito et al (1975). Mitsuma et al (1974) did not examine the crossreactivity of L-Pip3-TRF, although they mentioned that of L-Aze3-TRF was 2.5%.…”

Section: Discussionmentioning

confidence: 79%

Immunological and biological characteristics of a new TRF analogue, L-pyroglutamyl-L-histidyl-L-pipecolic acid amide.

1977

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“…Preliminary studies had shown that the pres- ence of plasma in the assay tubes apparently enhanced antibody binding of the hormone. Therefore, 300/al of TRH-free plasma, prepared by incubation of normal plasma at 37 C for 24 hr (Bassiri and Utiger, 1972b;Saito et al, 1975) was added to both standard curve and background tubes. Each assay tube received 300 /~1 of sample plasma, 300 /~1 of PBS-I% BSA, 100/al of anti-TRH sera (diluted 1:600), and 100/~1 of ]2s I-TRH in PBS~ BSA (approximately 40,000 cpm) and allowed to incubate at 4 C for 24 hours.…”

Section: Methodsmentioning

confidence: 99%

“…Blood was collected and immediately placed into centrifuge tubes containing 10 IU sodium heparin plus .75 mg (calculated on the basis of specific gravity) BAL (2, 3-dimercaptopropanol, Sigma) dispersed in water with .4 mg Tween 20 (polyoxyethylene sorbitan monolaurate, Sigma) per ml of blood and placed on ice. The BAL was added to prevent enzymatic degradation of TRH by plasma enzymes (Saito et al, 1975;Mitsuma et al, 1976). The enzyme inhibitor was dispensed into tubes to be used for blood collection as 100 gtl of an aqueous solution just prior to sample collection.…”

Section: Methodsmentioning

confidence: 99%

Estimation of Half-Life and Metabolic Clearance Rate of Thyrotropin-Releasing Hormone in Sheep Using a Double Antibody Radioimmunoassay

Klindt

Davis

Ohlson

1979

Journal of Animal Science

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Radioimmunoassay of Thyrotropin Releasing Hormone in Plasma and Urine

Cited by 19 publications

References 7 publications

Immunoreactive thyrotrophin-releasing hormone like material (IR-TRH LM) in human cord blood: high circulating serum levels but possible non-identity with hypothalamic TRH

Immunoreactive thyrotrophin-releasing hormone like material (IR-TRH LM) in human cord blood: high circulating serum levels but possible non-identity with hypothalamic TRH

Immunological and biological characteristics of a new TRF analogue, L-pyroglutamyl-L-histidyl-L-pipecolic acid amide.

Estimation of Half-Life and Metabolic Clearance Rate of Thyrotropin-Releasing Hormone in Sheep Using a Double Antibody Radioimmunoassay

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