GnRH, Gonadotropins, Gonadal Steroids and Reproduction

Interaction of Estrogen and Progesterone on Kisspeptin-10-Stimulated Luteinizing Hormone and Growth Hormone in Ovariectomized Cows
Brian K. Whitlock^a, Joseph A. Daniel^c, Robyn R. Wilborn^b, Soren P. Rodning^{b, d}, Herris S. Maxwell^b, Barbara P. Steele^a, James L. Sartin^a

Departments of
^aAnatomy, Physiology and Pharmacology and
^bClinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, Ala.,
^cDepartment of Animal Science, Berry College, Mt. Berry, Ga., and
^dDepartment of Animal Sciences, Auburn University, Auburn, Ala., USA

Address of Corresponding Author

Neuroendocrinology 2008;88:212-215 (DOI: 10.1159/000146242)

  Key Words

• Kisspeptin-10
• Growth hormone
• Luteinizing hormone

  Abstract

Background/Aims: Growth hormone (GH) is necessary for optimal reproductive efficiency and its secretion is influenced by sex steroids. This study was designed to determine whether kisspeptin-10 (Kp10) could stimulate GH and if gonadal steroids enhance the GH response to Kp10 in cows. Methods and Results: Intravenous injection of Kp10 at 100 or 200 pmol/kg body weight with or without treatment with estradiol cypionate and/or progesterone increased luteinizing hormone (p < 0.01) plasma concentrations. Plasma concentrations of GH were increased following Kp10 in cows treated with estradiol cypionate and/or progesterone (p < 0.05) but not in cows treated with Kp10 without gonadal steroids. Conclusions: These data suggest that reproductive steroids enhance the sensitivity of the somatotropic axis to physiologically relevant doses of Kp10, and support the possibility that Kp10 is an integrator of luteinizing hormone and GH release.

Copyright © 2008 S. Karger AG, Basel

  Author Contacts

James L. Sartin
Department of Anatomy, Physiology and Pharmacology
College of Veterinary Medicine, Auburn University
Auburn, AL 36849 (USA)
Tel. +1 334 844 5515, Fax +1 334 844 5388, E-Mail sartijl@vetmed.auburn.edu

  Article Information

Received: January 22, 2008
Accepted after revision: May 9, 2008
Published online: July 17, 2008
Number of Print Pages : 4
Number of Figures : 1, Number of Tables : 0, Number of References : 15