ISSN:
1573-5168
Keywords:
prolactin
;
bioassay
;
hormone variants
;
transepithelial potential
;
tilapia
;
Oreochromis mossambicus
;
red eft
;
Notophthalmus viridescens
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The cichlid fish tilapia (Oreochromis mossambicus) produces two forms of prolactin (tPRL177 and tPRL188) at equal rates. The primary sequences of this prolactin pair share only 69% identity. In these experiments, the whole-animal transepithelial potential (TEP) in the eft stage of the red-spotted newt (Notophthalmus viridescens) was measured in response to two injections totaling about 2 μg of tPRL177, tPRL188, ovine PRL, or tilapia growth hormone (tGH), or distilled water (5 μL/injection). This investigation was undertaken in order to locate prolactin receptors which discriminate between the two molecular forms of tilapia prolactin. The salamandrid integumental bioassay for prolactin was found to respond to tPRL177 as it does to ovine PRL. The more mainline tPRL188 was without effect at this dose and thus behaved more similarly to growth hormone (tilapia and ungulate) in this bioassay. The suspected magnitude of differences in the molecular surface characteristics between the two prolactins seem to be adequate to allow the binding of tPRL177 and to hinder the binding of tPRL188 to prolactin specific receptors in eft epithelial tissues.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00004697
Permalink
