Development, validation, and utilization of a novel antibody specific to the type III chicken gonadotropin-releasing hormone receptor

An updated model to describe the neuroendocrine control of reproduction in chickens

Since its first identification in quail 15 years ago, gonadotropin inhibitory hormone (GnIH) has become a central regulator of reproduction in avian species. In this review, we have revisited our original model published in 2009 to incorporate recent experimental evidence suggesting that GnIH acts as a molecular switch during the integration of multiple external and internal cues that allow sexual maturation to proceed in chickens. Furthermore, we discuss the regulation of a dual inhibitory/stimulatory control of the hypothalamo-pituitary-gonadal axis involving the interaction between GnIH and gonadotropin releasing hormone (GnRH). Finally, beyond seasonality, we also propose that GnIH along with this dual control may be responsible for the circadian control of ovulation in chickens, allowing eggs to be laid in a synchronized manner.

Morphological changes of gonadotropin-releasing hormone neurons in the rat preoptic area across puberty

Gonadotropin-releasing hormone (GnRH) neurons in the preoptic area may undergo morphological changes during the pubertal period when their activities are upregulated. To clarify the regulatory mechanism of puberty onset, this study aimed to investigate the morphological changes of GnRH neurons in the preoptic area of GnRH-enhanced green fluorescent protein transgenic rats. Under confocal laser microscopy, pubertal GnRH neurons exhibited an inverted Y distribution pattern. Prepubertal GnRH neurons were generally unipolar and bipolar, and were distinguished as smooth type cells with few small processes or irregular type cells with many spine-like processes in the proximal dendrites. The number of GnRH neurons in the preoptic area and spine-like processes were increased during the course of reproductive maturation. There was no significant difference between male and female rats. Immunofluorescence staining revealed synaptophysin punctae close to the distal end of GnRH neurons, indicating that some presynaptic terminals may form a synaptic linkage with these neurons.

Specificity evaluation of antibodies against human β3-adrenoceptors

β(3)-Adrenoceptors are a promising drug target for the treatment of urinary bladder dysfunction, but knowledge about their expression at the protein level and their functional role is limited, partly due to a lack of well validated tools. As many antibodies against G-protein-coupled receptors, including those against β(3)- and other β-adrenoceptor subtypes, lack selectivity for their target, we have evaluated the specificity of five antibodies raised against the full-length protein of the human β(3)-adrenoceptor (H155-B01), its N-terminus (LSA4198 and TA303277) and its C-terminus (AB5122, Sc1472) in immunoblotting and immunocytochemistry. Our primary test system were Chinese hamster ovary cells stably transfected to express each of the three human β-adrenoceptor subtypes at near physiological levels (100-200 fmol/mg protein). None of the five antibodies exhibited convincing target specificity in immunoblotting with Sc1472 apparently being least unsuitable. In immunocytochemistry, LSA4198 and Sc1472 appeared most promising, exhibiting at least some degree of specificity. As these two antibodies have been raised against different epitopes (N- and C-terminus of the receptor, respectively), we propose that concordant staining by both antibodies provides the most convincing evidence for β(3)-adrenoceptor labelling in cyto- or histochemistry studies.