Biomaterial Database

Absence of gonadal-hormone feedback on luteinizing hormone in both photorefractory and photosensitive white-crowned sparrows (Zonotrichia leucophrys gambelii). 1985

P W Mattocks

Elimination of gonadal-hormone feedback by castration from photorefractory male White-crowned sparrows in mid-July or early October, and from photosensitive males in early December, had no significant effect on plasma levels of LH. Photorefractory birds held on natural daylengths regained photosensitivity in the absence of gonadal-hormone feedback with no increase in plasma levels of LH. Implants of testosterone propionate into castrated males during November and December had no effect on plasma LH levels. These results indicate that gonadal-hormone feedback is not responsible for the very low levels of LH secretion in either the photorefractory or the photosensitive male White-crowned sparrow.

UI	MeSH Term	Description	Entries
D007986	Luteinizing Hormone	A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Luteinizing hormone regulates steroid production by the interstitial cells of the TESTIS and the OVARY. The preovulatory LUTEINIZING HORMONE surge in females induces OVULATION, and subsequent LUTEINIZATION of the follicle. LUTEINIZING HORMONE consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH and FSH), but the beta subunit is unique and confers its biological specificity.	ICSH (Interstitial Cell Stimulating Hormone),Interstitial Cell-Stimulating Hormone,LH (Luteinizing Hormone),Lutropin,Luteoziman,Luteozyman,Hormone, Interstitial Cell-Stimulating,Hormone, Luteinizing,Interstitial Cell Stimulating Hormone
D008027	Light	That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.	Light, Visible,Photoradiation,Radiation, Visible,Visible Radiation,Photoradiations,Radiations, Visible,Visible Light,Visible Radiations
D008297	Male		Males
D009919	Orchiectomy	The surgical removal of one or both testicles.	Castration, Male,Orchidectomy,Castrations, Male,Male Castration,Male Castrations,Orchidectomies,Orchiectomies
D010507	Periodicity	The tendency of a phenomenon to recur at regular intervals; in biological systems, the recurrence of certain activities (including hormonal, cellular, neural) may be annual, seasonal, monthly, daily, or more frequently (ultradian).	Cyclicity,Rhythmicity,Biological Rhythms,Bioperiodicity,Biorhythms,Biological Rhythm,Bioperiodicities,Biorhythm,Cyclicities,Periodicities,Rhythm, Biological,Rhythmicities,Rhythms, Biological
D012098	Reproduction	The total process by which organisms produce offspring. (Stedman, 25th ed)	Human Reproductive Index,Human Reproductive Indexes,Reproductive Period,Human Reproductive Indices,Index, Human Reproductive,Indexes, Human Reproductive,Indices, Human Reproductive,Period, Reproductive,Periods, Reproductive,Reproductive Index, Human,Reproductive Indices, Human,Reproductive Periods
D005246	Feedback	A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system.	Feedbacks
D005260	Female		Females
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001717	Birds	Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.	Aves,Bird