T
T. J. Nicholls
Researcher at University of Bristol
Publications - 7
Citations - 809
T. J. Nicholls is an academic researcher from University of Bristol. The author has contributed to research in topics: Prolactin & Luteinizing hormone. The author has an hindex of 7, co-authored 7 publications receiving 790 citations.
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Journal ArticleDOI
Photorefractoriness in birds and comparison with mammals
Journal ArticleDOI
Possible homologies between photorefractoriness in sheep and birds: the effect of thyroidectomy on the length of the ewe's breeding season.
TL;DR: It is argued that the two types of breeding cycle may not be so radically different as previously thought and, indeed, the cycles may be strictly homologous and evidence in support of this comes from the role of the thyroid glands in seasonality.
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Thyroidectomy prevents the development of photorefractoriness and the associated rise in plasma prolactin in starlings
TL;DR: It is confirmed that the presence of an intact thyroid gland is essential for the development of photorefractoriness and for the release of prolactin which normally follows photostimulation.
Journal ArticleDOI
Prolactin is associated with the development of photorefractoriness in intact, castrated, and testosterone-implanted starlings.
TL;DR: The timing of photorefractoriness and the associated rise in prolactin secretion which occur in response to photostimulation do not depend upon the presence of the gonads and are not affected when testosterone is maintained at a constant high level.
Journal ArticleDOI
Recovery of photosensitivity in photorefractory starlings is not prevented by testosterone treatment.
TL;DR: In the castrated birds given empty capsules plasma luteinizing hormone (LH) rose from basal levels after 20-30 days and reached a high plateau level at about 40 days; this return of a "castration response" indicates a quite rapid recovery of photosensitivity under short days.