title: Pituitary and plasma vasopressin concentrations and fluid balance throughout the oestrous cycle of the rat.
abstract: Observations were made of fluid balance and vasopressin concentrations throughout the oestrous cycle of normally cyclic female rats housed under a 12 h light: 12 h darkness regime. Plasma vasopressin concentrations were found to increase progressively during the light period, falling again during the night on all days of the cycle except pro-oestrus. On this day, peak vasopressin concentrations of 3.32 +/- 0.8 pmol/l were seen between 10.00 and 12.00 h, with lower concentrations of 1.74 +/- 0.22 pmol/l being seen between 18.00 and 19.00 h. Urine flow appeared to reflect the changes in plasma vasopressin concentrations, being significantly lower during the light phase, with a small increase being seen over this period on pro-oestrus. Pituitary vasopressin concentrations were highest between 09.00 and 10.00 h and fell progressively over each of the 4 days of the oestrous cycle. The changes in pituitary content were greater than could be accounted for in terms of the alterations in the plasma concentrations of vasopressin.
authors.affiliation: Department of Physiology, University College, London.
authors.forename: M L
authors.initials: ML
authors.lastname: Forsling
authors.forename: K
authors.initials: K
authors.lastname: Peysner
mesh_terms: D000818:Animals; D004971:Estrus / Q000502:physiology*; D005260:Female; D006400:Hematocrit; D010902:Pituitary Gland / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D014667:Vasopressins / Q000097:blood / Q000378:metabolism*; D014882:Water-Electrolyte Balance
chemical_list: D014667:Vasopressins