Outside of the pituitary, GnRHR expression (messenger
RNA [mRNA] and/or protein) has been reported in reproductive
and nonreproductive organs, including ovary, mammary
gland, testis, prostate, hypothalamus, heart, urinary
bladder, kidney, and liver. However, knowledge about the
receptor molecular configuration and function in extrapituitary
tissues remains fragmented and very limited. Based
on immunolocalization of GnRHR protein in human ovary,
Choi et al. [8] proposed a role of GnRHR in follicular developmentandcorpus
luteal function. SenguptaandSridaran[9]
evaluatedGnRHRmRNA and protein expression in oviduct at
time points important for the maintenance of pregnancy in
rats. The results pointed to an autocrine/paracrine role of
oviductal GnRH mediated by the receptor. To outline
extrapituitary roles for GnRHR, several studies quantified
GnRHR expression under various physiologic conditions. For
example, Coit et al. [10] demonstrated that sterilization was
associated with increased levels of GnRHR mRNA in urinary
bladder of male and female dogs. This effect was most pronounced
in female dogs with urinary incontinence, suggesting
that these two conditions might be related.
Expression of GnRHR in rat thymus after immunization
against GnRH showed that GnRHR plays a pivotal role as an
immunomodulator in thymus [11]. Albertson et al. [12] reportedGnRHRwithinthemammaliancerebellumsuggesting
a connection between cerebellar ataxia and hypogonadotropic
hypogonadism in patients with Gordon Homes and
Boucher-Neuhauser syndromes