General areas of interest:
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I am not ashamed to admit it, I like sheep. All my research to date has used the sheep model and has focused on understanding how GnRH secretion is regulated, both by melatonin and ovarian steroids. During these studies, I developed a novel method of extracting cerebrospinal fluid from specific compartments in the cerebroventricular system and analyzing this for several factors including melatonin, NPY and GnRH. This has also led to an interest in the precise function of GnRH in CSF and whether it is part of a “volume transmission” pathway for GnRH to be involved in sexual behavior. Recent studies have also investigated whether there is commonality in the neuronal pathways targeted by the glucocorticoids and ovarian steroids and whether these pathways overlap in the regulation of GHRH release. Techniques, like those shown in these photomicrographs, are used in the laboratory to characterize neural systems targeted by steroids. Using fluorescent tags, triple-labeled cell nuclei show that the majority of steroid receptive cells in the arcuate nuclei express progesterone, estrogen and glucocorticoid receptors. |
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To target the third ventricle, X-ray stereotaxy is employed. By extracting CSF and analyzing this for GnRH, it is clear that the release of this decapeptide in CSF accurately reflects its release in the hypophyseal portal system.
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Representative Papers (of +40) Dufourny LD & Skinner DC 2002 Distribution of type II glucocorticoid receptor-immunoreactive cells in the preoptic area and hypothalamus of the ewe: absence of colocalisation with GnRH neurones Brain Research In Press Skinner DC & Caraty A 2002 The measurement and possible function of GnRH in cerebrospinal fluid in ewes. Reproduction Suppl 59. In Press Scanlan N & Skinner DC 2002 Estradiol modulation of growth hormone secretion in the ewe: no growth hormone-releasing hormone neurons and few somatotropes express estradiol receptors. Biology of Reproduction 66: 1267-1273 Skinner DC, Caraty A & Allingham R 2001 Unmasking the progesterone receptor in the preoptic area and hypothalamus of the ewe: no colocalization with GnRH neurons. Endocrinology 142: 573-579 Skinner DC, Richter TA, Malpaux B & Skinner JD 2001 Annual ovarian cycles in an aseasonal breeder, the springbok (Antidorcas marsupialis) Biology of Reproduction 64: 1176-1182 Skinner DC, Harris TG & Evans NP 2000 The duration and amplitude of the luteal phase progesterone increment times the estradiol-induced LH surge in ewes. Biology of Reproduction 63: 1135-1142 Skinner DC & Malpaux B 1999 High melatonin concentrations in third ventricular cerebrospinal fluid are not due to Galen vein blood recirculating through the choroid plexus. Endocrinology 140: 4399-4405 Skinner DC, Evans NP, Bouchard P, Delaleu B & Caraty A 1998 The negative feedback actions of progesterone on gonadotropin-releasing hormone secretion are transduced by the classical progesterone receptor. Proceedings of the National Academy of Science 95: 10978-10983 Skinner DC & Herbison AE 1997 Effects of photoperiod on estrogen receptor, tyrosine hydroxylase, neuropeptide Y and ß-endorphin immunoreactivity in the ewe hypothalamus. Endocrinology 138:2585-2595 Skinner DC, Caraty A, Malpaux B & Evans NP 1997 Simultaneous measurement of GnRH in the third ventricular cerebrospinal fluid and hypophyseal portal blood of the ewe. Endocrinology 138: 4699-4704 Skinner DC & Robinson JE 1995 Melatonin-binding sites in the gonadotroph- enriched zona tuberalis of ewes. Journal of Reproduction and Fertility 104:243-250
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Double-labeling
with non-fluorescent chromogens reveals that GnRH neurons in the sheep preoptic
area do not express progesterone receptors. 
