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Influences of season and of temperature, photoperiod, and subcutaneous melatonin infusion on the glomerular filtration rate of ewes
Author(s) -
Tsuda Tsuneyuki,
Ide Masashi,
Iigo Masayuki
Publication year - 1995
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.1995.tb00185.x
Subject(s) - melatonin , photoperiodism , endocrinology , medicine , biology , filtration (mathematics) , renal function , zoology , statistics , mathematics
Influences of season and of temperature, photoperiod, and subcutaneous melatonin infusion on glomerular filtration rate (GFR) were measured in ewes. There was a seasonal difference of GFR between summer (June‐August) and winter (December‐February) in Tokyo (35°, 35°N); GFR was significantly ( P < 0.05) higher in summer (4.2 ± 0.3 ml/ min/kg) than in winter (3.0 ± 0.2 ml/min/kg). GFR was measured after exposure to three types of photoperiod, 24L: 0D, 12L: 12D, and 0L: 24D, for 7 to 8 days. The value for GFR obtained at 20°C was significantly lower ( P < 0.05) with 0L: 24D than with the other two photoperiodic conditions. GFR obtained during subcutaneous melatonin infusion (20μg/hr for 16 hr/ day for 7 days) with 24L: 0D conditions was significantly ( P < 0.05) lower (2.5 ± 0.1 ml/min/kg) than without infusion (3.8 ± 0.3 ml/ min/kg) and was about the same as that obtained in animals under 0L: 24D conditions. At 30°C, GFR exhibited no difference between the 3 photoperiodic conditions and was always lower than that found at 20°C. Possible influences of melatonin on GFR are discussed.