Biomaterial Database

The effect of different photoperiods on plasma concentrations of melatonin, prolactin, and cortisol in the domestic cat. 1984

H Leyva, and L Addiego, and G Stabenfeldt

These studies investigated the effects of photoperiod on plasma melatonin, PRL, and cortisol concentrations in cats. Animals were placed in one of three different photoperiod regimens [short (SP), 8 h of light, 16 h of darkness (8L:16D); normal (NP), 14L:10D; long (LP), 24L:OD] 140 days before experimentation (n = 4/group). In the first experiment, melatonin, PRL, and cortisol concentrations were measured in plasma obtained at 2-h intervals for 24 h. Peak melatonin concentrations were significantly different (P less than 0.05) in the groups with SP greater than NP greater than LP (9226 +/- 1052 vs. 3890 +/- 556 vs. 590 +/- 198 pg/ml, respectively). Melatonin concentrations declined significantly (P less than 0.01) during the last 2 h of dark in the SP animals, but not in NP animals. Acrophases for melatonin biorhythms occurred at 0030, 0430, and 0215 h for SP, NP, and LP, respectively. Significant regression coefficients were found for 8-, 12-, and 24-h cycles in the SP and for 8- and 24-h cycles in the NP (none in the LP). PRL concentrations were significantly higher during darkness in cats under a longer duration of dark with SP greater than NP greater than LP (164 +/- 5 vs. 57 +/- 3 vs. 26 +/- 7 ng/ml, respectively; P less than 0.05). Acrophases for SP and NP PRL biorhythms were similar (0145 vs. 0200 h, respectively), while exposure to a LP resulted in a major change in the acrophase (1200 h). Cortisol secretion was not affected by photoperiod. In the second experiment, animals entrained to SP for about 160 days were exposed to light at 2000 h for 12 h (6 h after lights off). Significant decreases (P less than 0.05) in PRL concentrations were noted within 2 h and in melatonin concentrations by 4 h (first sample analyzed). In a third experiment, animals entrained to a LP released significantly more PRL in response to TRH administration (P less than 0.001) than did those in NP and SP. The data indicate that melatonin and PRL secretion, but not cortisol secretion, are very responsive to changes in photoperiod in the cat.

UI	MeSH Term	Description	Entries
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
D008550	Melatonin	A biogenic amine that is found in animals and plants. In mammals, melatonin is produced by the PINEAL GLAND. Its secretion increases in darkness and decreases during exposure to light. Melatonin is implicated in the regulation of SLEEP, mood, and REPRODUCTION. Melatonin is also an effective antioxidant.
D011388	Prolactin	A lactogenic hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). It is a polypeptide of approximately 23 kD. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation. Prolactin receptors are present in the mammary gland, hypothalamus, liver, ovary, testis, and prostate.	Lactogenic Hormone, Pituitary,Mammotropic Hormone, Pituitary,Mammotropin,PRL (Prolactin),Hormone, Pituitary Lactogenic,Hormone, Pituitary Mammotropic,Pituitary Lactogenic Hormone,Pituitary Mammotropic Hormone
D011863	Radioimmunoassay	Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.	Radioimmunoassays
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D002940	Circadian Rhythm	The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs or environmental and physiological stimuli.	Diurnal Rhythm,Nyctohemeral Rhythm,Twenty-Four Hour Rhythm,Nycthemeral Rhythm,Circadian Rhythms,Diurnal Rhythms,Nycthemeral Rhythms,Nyctohemeral Rhythms,Rhythm, Circadian,Rhythm, Diurnal,Rhythm, Nycthemeral,Rhythm, Nyctohemeral,Rhythm, Twenty-Four Hour,Rhythms, Circadian,Rhythms, Diurnal,Rhythms, Nycthemeral,Rhythms, Nyctohemeral,Rhythms, Twenty-Four Hour,Twenty Four Hour Rhythm,Twenty-Four Hour Rhythms
D003624	Darkness	The absence of light.	Darknesses
D006854	Hydrocortisone	The main glucocorticoid secreted by the ADRENAL CORTEX. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions.	Cortef,Cortisol,Pregn-4-ene-3,20-dione, 11,17,21-trihydroxy-, (11beta)-,11-Epicortisol,Cortifair,Cortril,Epicortisol,Hydrocortisone, (11 alpha)-Isomer,Hydrocortisone, (9 beta,10 alpha,11 alpha)-Isomer,11 Epicortisol
D000064	Acclimatization	Adaptation to a new environment or to a change in the old.	Acclimation
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