Serum pattern of circulating free leptin, bound leptin, and soluble leptin receptor in the physiological menstrual cycle

Geisthövel, Franz; Jochmann, Nicoline; Widjaja, Adji; Horn, Rüdiger; Brabant, Georg

doi:10.1016/j.fertnstert.2003.06.020

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Volume 81, Issue 2 , Pages 398-402, February 2004

Serum pattern of circulating free leptin, bound leptin, and soluble leptin receptor in the physiological menstrual cycle☆

Presented in part at the 15th Annual Meeting of the European Society of Human Reproduction and Embryology, June 27–30, 1999, Tours, France.

Franz Geisthövel, M.D.
- Center for Gynecological Endocrinology and Reproductive Medicine, Freiburg im Breisgau, Freiburg i. Br., Germany
- Reprint requests: Franz Geisthövel, M.D., Center for Gynecological Endocrinology and Reproductive Medicine Freiburg, Kaiser-Josephstrasse 168, D-79098, Freiburg i. Br., Germany (FAX: 49-0761-32111).
Nicoline Jochmann, M.D.
- Department of Cardiology and Angiology, Charité/Campus-Mitte, Berlin, Germany
Adji Widjaja, M.D.
- Department of Gastroenterology, Hepatology, and Endocrinology, University Medical School, Hannover, Germany
Rüdiger Horn, B.Sc.
- Department of Gastroenterology, Hepatology, and Endocrinology, University Medical School, Hannover, Germany
Georg Brabant, M.D.
- Department of Gastroenterology, Hepatology, and Endocrinology, University Medical School, Hannover, Germany

Received 3 February 2003; received in revised form 19 June 2003; accepted 19 June 2003.

Abstract

Objective

To investigate the serum pattern of free leptin, bound leptin, and soluble leptin receptor throughout the physiological menstrual cycle.

Design

Prospective observational study.

Setting

Tertiary care center for gynecological endocrinology and reproductive medicine and a university research laboratory.

Patient(s)

Thirty regularly cycling volunteers (age, 29 ± 4.2 years).

Intervention(s)

Blood sampling was performed at different phases (early and mid follicular phase, preovulatory phase, and early and late luteal phase) of three consecutive menstrual cycles; each phase of the menstrual cycle was investigated twice.

Main outcome measure(s)

Free leptin, bound leptin, soluble leptin receptor, LH, E₂, P, vaginal ultrasound.

Result(s)

A peak of serum free leptin levels was found in the late luteal phase followed by a significant drop in the early follicular phase and again by a continuous increase up to the next luteal peak. There were no significant alterations in serum bound leptin and soluble leptin receptor levels.

Conclusion(s)

The present study shows that there are significant circacyclic fluctuations of free leptin levels with the highest concentrations in the late luteal phase and the lowest levels in the early follicular phase, which suggests that circulating free leptin is up-regulated by the C₂₁-steroid (P). Circulating bound leptin and soluble leptin receptor are not altered by the cyclic hormone status. The significant rise of the leptin bioequivalent, free leptin, in the late luteal phase might be of importance for the luteal-follicular and the luteal-preimplantatory functional shift.

Keywords: Free leptin, bound leptin, soluble leptin receptor, circacyclic fluctuation, physiological menstrual cycle