The half-life, metabolism and excretion of tritiated luteinizing hormone-releasing hormone (Lh-rh) in man

T. W. Redding; A. J. Kastin; D. Gonzalez-Barcena; D. H. Coy; E. J. Coy; D. S. Schalch; Andrew V Schally

doi:10.1210/jcem-37-4-626

The half-life, metabolism and excretion of tritiated luteinizing hormone-releasing hormone (Lh-rh) in man

T. W. Redding, A. J. Kastin, D. Gonzalez-Barcena, D. H. Coy, E. J. Coy, D. S. Schalch, Andrew V Schally

Original language	English (US)
Pages (from-to)	626-631
Number of pages	6
Journal	Journal of Clinical Endocrinology and Metabolism
Volume	37
Issue number	4
DOIs	https://doi.org/10.1210/jcem-37-4-626
State	Published - 1973
Externally published	Yes

ASJC Scopus subject areas

Endocrinology, Diabetes and Metabolism
Biochemistry
Endocrinology
Clinical Biochemistry
Biochemistry, medical

Cite this

Redding, T. W., Kastin, A. J., Gonzalez-Barcena, D., Coy, D. H., Coy, E. J., Schalch, D. S., & Schally, A. V. (1973). The half-life, metabolism and excretion of tritiated luteinizing hormone-releasing hormone (Lh-rh) in man. Journal of Clinical Endocrinology and Metabolism, 37(4), 626-631. https://doi.org/10.1210/jcem-37-4-626

@article{b2301d6e6a1a437a984e71b033944ffb,

title = "The half-life, metabolism and excretion of tritiated luteinizing hormone-releasing hormone (Lh-rh) in man",

abstract = "Synthetic3H-labeled luteinizing hormone-releasing hormone (LH-RH) with a specific activity of 18.3 Ci/mM and the same biological activity as pure porcine LH-RH was used to study the half-life, metabolism and urinary excretion of LH-RH in man. Seven healthy men were given a rapid iv injection of 42 μCi of3H-LH-RH, followed in 6 of the subjects by 250 Hg unlabeled LH-RH. Frequent samples of blood and urine were collected. There was a mean maximum increase in plasma levels of LH of 963% and FSH of 312% in samples obtained 30 min after injection. A plot of the disappearance times in the plasma was characteristic of a multiexponential curve. The half-life of the first exponential curve, which probably represents the half-life of LH-RH in man, was 4 min and for the second curve was 57 min. The distribution volume, when expressed as a percentage of body weight was 8.7%. One hr after the injection of the labeled LH-RH, 48.2 ± 5.4% of the dose of radioactivity was found in the urine and after 24 hr 73.5 ± 5.4% had been excreted. Extraction of the urine followed by chromatography on carboxymethyl cellulose and thin-layer electrophoresis showed most of the radioactivity to be associated with pyroglutamic acid (5-10%) and the dipeptide, pyroglutamyl-histidine (80-90%). None of the radioactivity was found in areas with the same Rf as LH-RH itself. These data suggest that one of the mechanisms for inactivation of LH-RH is the cleavage of pyroglutamyl-histidine moiety from the N-terminus of LH-RH.",

author = "Redding, {T. W.} and Kastin, {A. J.} and D. Gonzalez-Barcena and Coy, {D. H.} and Coy, {E. J.} and Schalch, {D. S.} and Schally, {Andrew V}",

year = "1973",

doi = "10.1210/jcem-37-4-626",

language = "English (US)",

volume = "37",

pages = "626--631",

journal = "Journal of Clinical Endocrinology and Metabolism",

issn = "0021-972X",

publisher = "The Endocrine Society",

number = "4",

}

TY - JOUR

T1 - The half-life, metabolism and excretion of tritiated luteinizing hormone-releasing hormone (Lh-rh) in man

AU - Redding, T. W.

AU - Kastin, A. J.

AU - Gonzalez-Barcena, D.

AU - Coy, D. H.

AU - Coy, E. J.

AU - Schalch, D. S.

AU - Schally, Andrew V

PY - 1973

Y1 - 1973

N2 - Synthetic3H-labeled luteinizing hormone-releasing hormone (LH-RH) with a specific activity of 18.3 Ci/mM and the same biological activity as pure porcine LH-RH was used to study the half-life, metabolism and urinary excretion of LH-RH in man. Seven healthy men were given a rapid iv injection of 42 μCi of3H-LH-RH, followed in 6 of the subjects by 250 Hg unlabeled LH-RH. Frequent samples of blood and urine were collected. There was a mean maximum increase in plasma levels of LH of 963% and FSH of 312% in samples obtained 30 min after injection. A plot of the disappearance times in the plasma was characteristic of a multiexponential curve. The half-life of the first exponential curve, which probably represents the half-life of LH-RH in man, was 4 min and for the second curve was 57 min. The distribution volume, when expressed as a percentage of body weight was 8.7%. One hr after the injection of the labeled LH-RH, 48.2 ± 5.4% of the dose of radioactivity was found in the urine and after 24 hr 73.5 ± 5.4% had been excreted. Extraction of the urine followed by chromatography on carboxymethyl cellulose and thin-layer electrophoresis showed most of the radioactivity to be associated with pyroglutamic acid (5-10%) and the dipeptide, pyroglutamyl-histidine (80-90%). None of the radioactivity was found in areas with the same Rf as LH-RH itself. These data suggest that one of the mechanisms for inactivation of LH-RH is the cleavage of pyroglutamyl-histidine moiety from the N-terminus of LH-RH.

AB - Synthetic3H-labeled luteinizing hormone-releasing hormone (LH-RH) with a specific activity of 18.3 Ci/mM and the same biological activity as pure porcine LH-RH was used to study the half-life, metabolism and urinary excretion of LH-RH in man. Seven healthy men were given a rapid iv injection of 42 μCi of3H-LH-RH, followed in 6 of the subjects by 250 Hg unlabeled LH-RH. Frequent samples of blood and urine were collected. There was a mean maximum increase in plasma levels of LH of 963% and FSH of 312% in samples obtained 30 min after injection. A plot of the disappearance times in the plasma was characteristic of a multiexponential curve. The half-life of the first exponential curve, which probably represents the half-life of LH-RH in man, was 4 min and for the second curve was 57 min. The distribution volume, when expressed as a percentage of body weight was 8.7%. One hr after the injection of the labeled LH-RH, 48.2 ± 5.4% of the dose of radioactivity was found in the urine and after 24 hr 73.5 ± 5.4% had been excreted. Extraction of the urine followed by chromatography on carboxymethyl cellulose and thin-layer electrophoresis showed most of the radioactivity to be associated with pyroglutamic acid (5-10%) and the dipeptide, pyroglutamyl-histidine (80-90%). None of the radioactivity was found in areas with the same Rf as LH-RH itself. These data suggest that one of the mechanisms for inactivation of LH-RH is the cleavage of pyroglutamyl-histidine moiety from the N-terminus of LH-RH.

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U2 - 10.1210/jcem-37-4-626

DO - 10.1210/jcem-37-4-626

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AN - SCOPUS:0015905910

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SP - 626

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JO - Journal of Clinical Endocrinology and Metabolism

JF - Journal of Clinical Endocrinology and Metabolism

SN - 0021-972X

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