Effects of long-term dietary soy treatment on female urethral morphology and function in ovariectomized nonhuman primates.
OBJECTIVE
Agonistic effects of estrogen on the female urethra include an increase in contractile function, blood flow and mucosal hyperplasia. Whether such effects can be achieved by soy based phytoestrogen diets is unclear. We studied the effects of chronic phytoestrogen treatment on the structural and functional properties of the urethra in ovariectomized monkeys.


METHODS
Following ovariectomy 18 monkeys were fed a diet containing soy (9) or casein (9) based protein for 32 months. At necropsy the urethra and bladder were removed and the urethra was separated into 3 segments of equal length, including a proximal, a middle and a distal segment. Each urethral segment and 1 bladder segment was tested in vitro for functional responses to electrical field stimulation and pharmacological stimulation, and the proximal to distal segments were tested for urothelial thickness and mucosal area.


RESULTS
Electrical field stimulation produced frequency dependent contractile responses in the bladder, proximal and middle segments but not in the distal segment. Carbachol, phenylephrine and endothelin-1 produced concentration dependent contractions in all urethral segments. The maximum response decreased from the proximal to the distal segment (p </=0.05). The maximum response in the proximal and bladder segments to pharmacological stimulation and electrical field stimulation as well as mucosal area and urothelial thickness were significantly higher in the treatment than in the control group (p < or =0.05).


CONCLUSIONS
Chronic phytoestrogen treatment results in increased responsiveness of the proximal urethra to pharmacological and electrical stimulation, which is associated with an increase in urothelial thickness and mucosal area. This study indicates that dietary soy may have estrogen agonist effects on the urethra and bladder in estrogen deficient females.
Gratzke
Christian
C
Wake Forest Institute for Regenerative Medicine, Wake Forest University, Winston-Salem, North Carolina 27157, USA.
Jarajapu
Yagna P R
YP
Christ
George J
GJ
Kaplan
Jay R
JR
Williams
J Koudy
JK
Andersson
Karl-Erik
KE
Badlani
Gopal
G
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D004044:Dietary Proteins / Q000494:pharmacology*; D004195:Disease Models, Animal; D005260:Female; D007150:Immunohistochemistry; D008252:Macaca fascicularis; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D010052:Ovariectomy / Q000379:methods; D010656:Phenylephrine / Q000494:pharmacology; D011336:Probability; D011897:Random Allocation; D012016:Reference Values; D012680:Sensitivity and Specificity; D030262:Soybean Proteins / Q000494:pharmacology*; D013997:Time Factors; D046509:Tissue Culture Techniques; D014521:Urethra / Q000187:drug effects* / Q000473:pathology*
D004044:Dietary Proteins; D030262:Soybean Proteins; D010656:Phenylephrine; D002217:Carbachol