Biologia De La Reproduccion

BIOLOGY OF REPRODUCTION 82, 132–135 (2010)
Published online before print 14 August 2009.
DOI 10.1095/biolreprod.109.078857

Porcine Vas Deferens Luminal pH Is Acutely Increased by Systemic
Xylazine Administration1
Fernando Pierucci-Alves,2,3 Cameron L. Duncan,3 James D. Lillich,4 and Bruce D. Schultz3
Departments of Anatomy & Physiology3 and Clinical Sciences,4 Kansas State University,Manhattan, Kansas

Data are accumulating to demonstrate that pH regulation in
the male reproductive tract has a vital role in modulating sperm
cell fertilizing capacity, and therefore male fertility. Bicarbonate
uptake by sperm cells is required for the achievement of motility
levels required for fertilization. Vas deferens epithelial cells can
carry out measurable bicarbonate secretion, butthe available
literature to date reports that the vas deferens luminal content is
typically acidic. This study aimed to determine pH in the boar
vas deferens lumen and whether modulatory mechanisms exist
for regulation of pH in this compartment of the male
reproductive tract. A fiberoptic pH probe was used to assess
pH in the vas deferens of anesthetized adult boars. The mean
pH, derivedfrom multiple measurements at variable positions
along the vas deferens lumen, was 7.39 6 0.09. Furthermore,
administration of xylazine, an alpha-2 adrenergic receptor
agonist rapidly (,10 min) alkalinized the vas deferens lumen
in most cases. Because the duct was transected proximal to the
site of measurements, the observations rule out the possibility
that alkalinization resulted fromsecretion in more proximal
portions of the duct. These results indicate that the boar vas
deferens lumen can be alkaline, and they suggest that porcine
vas deferens epithelia increase net bicarbonate secretion in vivo
after systemic alpha-2 adrenergic stimulation. This secretory
response greatly changes the luminal environment to which
sperm cells are exposed, which will initiate or enhancemotility,
and is expected to modulate male fertility.
male reproductive tract, vas deferens

INTRODUCTION
Defined pH levels in specific compartments of the mammalian male reproductive tract are required for male fertility [1, 2].
A phenotype that included increased epididymal pH, reduced
sperm motility, abundant sperm tail defects, and male infertility
was described in a knockout mousemodel in which expression
of the V-ATPase proton pump and bicarbonate exchanger
SLC26A4 were disrupted [1]. Additionally, data derived from
mice heterozygous for the cystic fibrosis conductance transmembrane regulator (CFTR) revealed that bicarbonate uptake
through CFTR expressed in sperm cells is required for the
1
Supported by National Institutes of Health (NIH) grant no. HD058398
and NIHgrant no. RR17686. This manuscript represents contribution
no. 09-337-J from the Kansas Agricultural Experiment Station.
2
Correspondence: Fernando Pierucci-Alves, Department of Anatomy &
Physiology, Kansas State University, 1600 Denison Ave., Coles Hall
228, Manhattan, KS 66506. FAX: 785 532 4557;
e-mail: falves@vet.ksu.edu

MATERIALS AND METHODS
Animals and Surgical ProcedureReceived: 14 May 2009.
First decision: 6 June 2009.
Accepted: 4 August 2009.
Ó 2010 by the Society for the Study of Reproduction, Inc.
eISSN: 1529-7268 http://www.biolreprod.org
ISSN: 0006-3363

A total of 12 boars were employed in this protocol, which was reviewed
and approved by the Kansas State University Institutional Animal Care and Use
Committee. Boars were mixed breed, sexually mature andactive, purchased
from local swine facilities, and transported to the Large Animal Section of the
Veterinary Medical Teaching Hospital at Kansas State University on the day

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achievement of sperm motility levels suitable for fertilization [2].
At the clinical level, men carrying dysfunctional mutations for
the bicarbonate exchanger SLC26A3 are...