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This Article Full Text Full Text (PDF) All Versions of this Article: 295/1/E130    most recent 90300.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Suter, K. J. Articles by O'Farrell, L. Search for Related Content PubMed PubMed Citation Articles by Suter, K. J. Articles by O'Farrell, L.

Impaired episodic LH secretion in female mice with GFP in GnRH neurons

¹Department of Biology, University of Texas at San Antonio, San Antonio, Texas; and ²Georgia State University, Atlanta, Georgia

Submitted 19 March 2008 ; accepted in final form 20 May 2008

The ability to assess the activity of gonadotropin-releasing hormone (GnRH) neurons has been greatly enhanced by transgenic animal models with targeted expression of green fluorescent protein (GFP). However, it has yet to be demonstrated that the GnRH system continues to exhibit a full range of normal physiological functions in the presence of such genetic manipulation. Accordingly, we have used repetitive blood sampling via indwelling venous catheters to define LH secretory patterns in normal and transgenic mice. Transgenic females proved to be reproductively competent as defined by fecundity, appropriate cyclic changes in vaginal cytology in intact adult females, and spontaneous LH surges as well as surges in response to steroid or mating stimuli. The expression of c-fos following such steroid treatment and mating in ovariectomized transgenics was similar to the expression previously reported in nontransgenic mice. Likewise, the percentage of retrogradely labeled GnRH neurons was similar to that reported in nontransgenic mice. However, episodic LH secretion, an index of GnRH pulse generator activity, was dramatically compromised in ovariectomized female transgenics compared with C57BL6 controls of both sexes and castrated transgenic males. Taken together, these findings suggest that the GnRH pulse generator is selectively impaired in ovariectomized females in which GnRH neurons express GFP.

luteinizing hormone; green fluorescent protein; transgenic mouse; luteinizing hormone secretion; gonadotropin-releasing hormone