Aj. Devlin et al., IMMUNOCHEMICAL DETECTION OF PARATHYROID HORMONE-RELATED PROTEIN IN THE SACCUS VASCULOSUS OF A TELEOST FISH, General and comparative endocrinology, 101(1), 1996, pp. 83-90
Using antisera to regions of human parathyroid hormone-related protein
(PTHrP) the saccus vasculosus (SV) of the sea bream (Sparus aurata) h
as been shown to contain immunoreactive PTHrP. By immunohistochemistry
(IHC) the epithelial coronet cells in fixed and wax-embedded SV tissu
e reacted with antisera to the prepro region of human PTHrP (-13 to +2
), the N-terminus PTHrP (1-16), and the midmolecule PTHrP (50-69). Sod
ium dodecyl sulfate-polyacrylamide gel electrophoresis of saccus extra
cts and incubation media contained two major proteins of 14.3 and 15 k
Da. By Western blotting these two proteins both reacted with the three
antisera used for IHC, suggesting that they are immunochemically simi
lar to human PTHrP (1-84). Ultrastructurally the coronet cells of Spar
us saccus vasculosus resembled coronet cells described for other teleo
sts, with an abundant smooth endoplasmic reticulum (SER) which was mor
e highly organized in the coronets. IHC at EM level showed reaction ma
inly with the membranes of the SER. These results suggest that S. aura
ta saccus vasculosus may produce a PTHrP-like molecule similar to huma
n PTHrP. (C) 1996 Academic Press, Inc.