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Oestrogen effects on urine concentrating response in young women
Author(s) -
Stachenfeld Nina S.,
Taylor Hugh S.,
Leone Cheryl A.,
Keefe David L.
Publication year - 2003
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2003.046920
Subject(s) - endocrinology , medicine , vasopressin , chemistry , arginine , urine , hormone , urine osmolality , sodium , plasma osmolality , amino acid , biochemistry , organic chemistry
Oestrogen lowers the plasma osmotic threshold for arginine vasopressin (AVP) release but without commensurate changes in renal concentrating response, suggesting oestrogen (OE 2 ) may lower renal sensitivity to AVP. Ten women (23 ± 1 years) received a gonadotropin releasing hormone analogue (GnRHa), leuprolide acetate, to suppress OE 2 for 35 days, and then added OE 2 (two patches each delivering 0.1 mg day −1 ) on days 32–35. On days 28 and 35 we tested blood and renal water and sodium (Na + ) regulation during stepwise 60 min AVP infusions (10, 35, 100, 150 and 200 μ u (kg body weight) −1 Pitressin). Plasma OE 2 concentration increased from 19 ± 4 to 152 ± 3 pg ml −1 and plasma progesterone concentration was unchanged (1.0 ± 0.4 and 0.7 ± 0.1 ng ml −1 ) for GnRHa and OE 2 administration, respectively. Standard log plots of plasma AVP concentration ([AVP] P ) vs. urine osmolality (Osm U ) were fitted to a sigmoidal curve, and EC 50 was determined by non‐linear regression curve fitting of concentration‐response data. Osm U rose exponentially during AVP infusions, but hormone treatments did not affect EC 50 (3.3 ± 0.07 and 3.1 ± 0.6 pg ml −1 , for GnRHa and OE 2 , respectively). However, the urine osmolality increase was greater within the physiological range (˜2.5−3.4 pg ml −1 [AVP] P ) during OE 2 treatment. Throughout most of the AVP infusion, the rate of clearance of AVP from plasma (PCR AVP ) was increased during OE 2 (45.5 ml (kg body weight) −1 min −1 ) compared to GnRHa administration (33.1 ml (kg body weight) −1 min −1 ; mean for the 100–200 μ u (kg body weight) −1 infusion rates). The rate of renal free water clearance ( C H2O ) was similar between hormone treatments. Sodium excretion fell during OE 2 administration due to greater distal tubular sodium reabsorption. Despite more rapid PCR AVP , renal concentrating response to graded AVP infusions was unaffected by oestrogen treatment suggesting oestrogen does not affect overall renal sensitivity to AVP. However, OE 2 may increase renal fluid retention within a physiological range of AVP.