Domestic Animal Endocrinology 34 (2008) 339–351 Available online at www.sciencedirect.com Differences in the expression of luteinizing hormone and follicle-stimulating hormone receptors in the lower urinary tract between intact and gonadectomised male and female dogs S. Ponglowhapan, D.B. Church, M. Khalid ∗ Department of Veterinary Clinical Sciences, The Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire AL9 7TA, UK Received 11 May 2007; received in revised form 22 September 2007; accepted 24 September 2007 Abstract Receptors for LH (LHR) and FSH (FSHR) are expressed in the canine lower urinary tract (LUT). As gonadectomy results in an increase in plasma LH and FSH, the objective of this study was to determine whether there are any differences in the expression of LHR and FSHR in the LUT between intact and gonadectomised dogs. Four regions of the LUT, i.e. body and neck of the bladder as well as proximal and distal urethra, were collected from 20 healthy dogs (5 intact males, 5 intact anoestrous females, 4 castrated males and 6 spayed females). The mRNA and protein expression of receptors was determined by in situ hybridization and immunohistochemistry, respectively, and assessed semi-quantitatively incorporating both the distribution and the intensity of specific staining. Expression of LHR and FSHR was present in all tissue layers (epithelium, sub-epithelial stroma and muscle) of each region with different levels of the expression. Overall mRNA and protein expression for both LHR and FSHR was significantly (P < 0.001) lower in gonadectomised dogs. Intact dogs had more (P < 0.05) LHR and FSHR mRNA and protein in all tissue layers of the four regions, except for LHR mRNA expression in the sub-epithelial stroma where no differences were observed between the two statuses. Decreases in LHR and FSHR mRNA and protein in gonadectomised dogs appeared to be more consistent in spayed bitches compared to castrated males. Lower expression of LHR and FSHR observed in gonadectomised dogs may adversely affect the normal canine LUT function. © 2007 Elsevier Inc. All rights reserved. Keywords: Dog; Urinary incontinence; Gonadotrophins; Spaying; Castration 1. Introduction Pituitary gonadotrophins (luteinizing hormone, LH and follicle-stimulating hormone, FSH) have previously been considered to regulate only ovarian and testicu- lar functions because traditionally only these tissues were thought to contain LH and FSH receptors. How- ever, increasing evidence shows that LH and FSH ∗ Corresponding author. Tel.: +44 1707 666539. E-mail address: mkhalid@rvc.ac.uk (M. Khalid). can also affect functions of organs other than gonads. The potential association between gonadotrophins and pathophysiology of lower urinary tract (LUT) was first suggested by Tao et al. [1] by demonstrating expres- sion of LH/hCG receptors in the human urinary bladder with a significant reduction in receptor density in post- menpopausal women, compared to the premenopausal subjects. In dogs, a successful treatment of post-spaying urinary incontinence using depot GnRH analogues that lowered plasma LH and FSH concentrations [2] has led to the suggestion that there might be a functional rela- tionship between gonadotrophins and the canine LUT. If 0739-7240/$ – see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.domaniend.2007.09.005