This Article Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints, Permissions and Rights Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by KAPLAN, S. L. Articles by GRUMBACH, M. M. Search for Related Content PubMed PubMed Citation Articles by KAPLAN, S. L. Articles by GRUMBACH, M. M.

Metabolic Clearance Rate and Production Rate of Chorionic Growth Hormone-Prolactin in Late Pregnancy

Department of Pediatrics, Biochemistry, College of Physicians and Surgeons, Columbia University New York, New York
Department of Obstetrics, College of Physicians and Surgeons, Columbia University New York, New York
Department of Gynecology, College of Physicians and Surgeons Columbia University New York, New York
Department of Pediatrics, University of California, San Francisco Medical Center San Francisco, California 94122

The metabolic clearance rate (MCR) and production rate (PR) of circulating chorionic growth hormone-prolactin (CGP) were estimated from measurements of plasma concentrations of endogenous CGP following delivery of the placenta and of ¹³¹I-CGP following intravenous administration of the tracer. The MCR did not vary appreciably in the 3 pregnant and 4 nonpregnant subjects who were studied by the tracer method; the mean value was 173 1/day. At delivery, the PR estimated by this procedure was 1.03 g/day. Utilizing the rate of disappearance of endogenous CGP from plasma following delivery of the placenta in 6 pregnant women and a volume of distribution estimated from the tracer experiments, a mean PR of 1.78 g/day was found. Both the tracer and endogenous CGP disappearance curves could be resolved into at least 2 exponential components. The validity of the calculations of MCR and PR by these methods is discussed. The results of the studies of MCR in the light of other evidence suggest that the concentration of plasma CGP is directly proportional to PR, and the determination of plasma CGP in random samples of pregnancy blood provides a useful index of the production rate in contrast to estimations of the 24-hr urinary excretion. Only a small proportion of the total PR of CGP appears in the urine. Further support was obtained for the virtually unidirectional secretion of CGP into the maternal circulation. No evidence of sequestration of circulating CGP by the placenta was detected.

This work was supported in part by grants from the National Institutes of Child Health and Human Development, NIH, USPHS.

¹ Recipient of a Career Development Award, NIH.

² Present address: Department of Pediatrics, University of California, San Francisco Medical Center, San Francisco, Cal. 94122.

³ Career Scientist, Health Research Council of The City of New York.

Received June 16, 1967.

Accepted June 25, 1968.

This article has been cited by other articles:

				T. M Lovell, R. J Woods, D. J Butlin, K. J Brayley, I. T Manyonda, J. Jarvis, S. Howell, and P. J Lowry Identification of a novel mammalian post-translational modification, phosphocholine, on placental secretory polypeptides J. Mol. Endocrinol., September 1, 2007; 39(3): 189 - 198. [Abstract] [Full Text] [PDF]