BOR - Papers in Press, published online ahead of print
June 23, 2004.
Biol Reprod 2004, 10.1095/biolreprod.104.031401
BIOLOGY OF REPRODUCTION 71, 15081516 (2004)
DOI: 10.1095/biolreprod.104.031401
© 2004 by the Society for the Study of Reproduction, Inc.
Composition of Luminal Fluid Secreted by the Seminiferous Tubules and After Reabsorption by the Extratesticular Ducts of the Japanese Quail, Coturnix coturnix japonica1
J. Clulow, and
R.C. Jones2
Discipline of Biological Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
The present report examines the composition of luminal fluid in the seminiferous tubule (STF), rete testis (RTF), and ductus epididymidis of the Japanese quail (Coturnix coturnix japonica). This subject is of particular interest, both because the reproductive ducts are intra-abdominal and because sperm production is more rapid in birds than in mammals. It was interpreted that micropuncture samples of STF contain varying amounts of contamination with intracellular solute, particularly K and protein. The concentration of solute in samples was correlated with packed cell volume (spermatocrit), and when the latter was used to assess estimates of solute concentration in STF, the magnitude of the estimates were much the same as determinations in RTF. Consequently, it is concluded that the fluid entering the rete testis of the quail is the primary secretion of the seminiferous tubules. The composition of RTF in the quail was determined to be 148 mM Na, 126 mM Cl, 9.8 mM K, 2.7 mM Mg, 1.4 mM Ca, 2.1 mM glutamate, 3.4 mM glutamine, 20.2 mM bicarbonate, 1.8 µg µl1 of protein, pH 7.34, and 310 mmol kg1, and it is significantly different from the composition of blood plasma. Estimates of solute output by the testis and reabsorption by the extratesticular ducts indicate, first, that most of the solutes secreted into the seminiferous tubules are subsequently reabsorbed from the extratesticular ducts and, second, that sufficient solute of testicular origin (except for protein) exists to account for the concentrations of solutes throughout the lumen of the duct system. Changes in the concentration of solute in the extratesticular ducts probably result from different reabsorption rates of solute and water. The composition of fluid from the distal end of the ductus epididymidis was 133 mM Na, 125 mM Cl, 25 mM K, 1.0 mM Mg, 0.3 mM Ca, 6.7 mM glutamate, 4.0 mM glutamine, 19.5 mM bicarbonate, 6.0 µg µl1 of protein, pH 7.33, and 335 mmol kg1, and it is significantly different from those of RTF and blood.
1 Supported by grants from the Australian Research Council, The Research Management Committee, University of Newcastle, and a Commonwealth Postgraduate scholarship to J.C.
2 Correspondence. FAX: 61 2 4921 6923; bircj{at}cc.newcastle.edu.au
Copyright © 2004 by the Society for the Study of Reproduction.