A comparison of prolactins from a marine, an estuarine, and a freshwater teleost

Ng, T.B.; Idler, D. R.; Burton, Margaret

doi:10.1016/0016-6480(80)90268-3

Cited by 14 publications

(2 citation statements)

References 31 publications

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“…cordance with the description made in sole by Nunez-Rodriguez (1985), also using an anti-carp p-GtH and comparing with classical histology. Prolactin cells revealed by an anti-salmon PRL are localized in the rostral pars distalis as described for winter flounder (Ng et al, 1980) and sole (NunezRodriguez, 1985) with the same antibody as ours.…”

Section: Gnrh Receptor Binding Activitysupporting

confidence: 69%

Evidence of GnRH receptors in cultured pituitary cells of the winter flounder (Pseudopleuronectes americanus W.)

Weil

Crim

Wilson

et al. 1992

General and Comparative Endocrinology

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For continued studies of GnRH receptor regulation in the winter flounder, we have developed an in vitro system consisting of cultured pituitary cells dissociated by collagenase. Using immunocytochemical staining methods for gonadotropin, growth hormone, and prolactin, these cell types were represented at the levels of 25, 20, and 19.5% of total pituitary cell population, respectively. Receptors for GnRH were characterized in intact monolayered attached pituitary cells, maintained in RPM1 culture medium. The cell GnRH receptor characteristics were compared with those previously described using pituitary homogenates. The cells were capable of binding GnRH in a similar manner on Day 2 or Day 3 of culture, indicating the integrity of GnRH receptors. The specificity of binding was demonstrated since only high doses of cold GnRHa competed with "'1-GnRHa uptake, different peptides being without effect. The specific binding is saturable and the data suggest the presence of a single class of high-affinity (apparent K, = 1.50 x 109 M-l), high-capacity sites (binding capacity = 25.03 fmoY2.5 X lo5 cells or 242.23 X IO3 sites/gonadotroph) which is in accordance with the characteristics of GnRH receptors present in homogenates of pooled male and female pituitary glands. All these observations suggest that such an in vitro pituitary cell system would be appropriate for studying GnRH receptor characteristics under different physiological conditions. 8 1992 Academic press, IX.

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Section: Gnrh Receptor Binding Activitysupporting

confidence: 69%

Evidence of GnRH receptors in cultured pituitary cells of the winter flounder (Pseudopleuronectes americanus W.)

Weil

Crim

Wilson

et al. 1992

General and Comparative Endocrinology

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“…The first purification procedure adapted from Idler et al (1978) and Ng et al (1980) did not allow us to get pure chinook salmon prolactin. However, we obtained a preparation in which chinook salmon prolactin was the main protein as indicated by elec- In all cases insulin was present at the concentration of 5 ug/ml.…”

Section: Discussionmentioning

confidence: 99%

Purification and biological characterization of chinook salmon prolactin

Prunet

Houdebiné

1984

General and Comparative Endocrinology

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Prolactin from chinook salmon pituitaries was purified by acid acetone extraction, saline precipitation, chromatofocusing, and gel filtration. This procedure allowed us to recover highly purified prolactin as demonstrated by the presence of a single NH2-terminal amino acid and a single band in sodium dodecyl sulfate gel electrophoresis. Chinook salmon prolactin appeared to be a basic protein of 22,500 molecular weight. Throughout the purification, prolactin bioactivity was followed by radioreceptor assay for lactogenic hormones. The prolactin character of the purified protein was established by its lactogenic activity in the rabbit mammary gland in vitro and its sodium-retaining activity in hypophysectomized Fundulus heteroclitus.

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Response of male brown bullhead catfish, Ictalurus nebulosus lesueur, to gonadotropin‐releasing hormone and gonadotropin

Rosenblum¹,

Callard²

1987

J. Exp. Zool.

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These studies were performed in order to investigate the roles of GnRH and GtH in the regulation of reproductive function in male brown bullhead catfish, Ictalurus nebulosus. Adult catfish were given intravenous injections of salmon GtH (SG-G100) or salmon GnRH (sGnRH), and plasma testosterone, 11-ketotestosterone, and estradiol-17P levels were measured. SGGlOO elicited parallel increases in testosterone and 11-ketotestosterone, with peak levels between 8-12 hr after treatment. The effects of SG-G100 on plasma testosterone were dose-dependent, whereas increased 11-ketotestosterone was only seen with the two highest doses. Treatment with sGnRH elicited increased testosterone at 4 hr, and 11-ketotestosterone between 4-24 hr posttreatment. No clear dose-response to sGnRH was observed. The effects of SGGlOO and sGnRH varied with the annual reproductive cycle. During early testicular recrudescence in May, both the pituitary and testis were sensitive to trophic stimulation, with 2-to 4-fold increases in plasma androgens following sGnRH and SG-G100. Neither treatment was effective in mature animals trapped in July. In November, despite low basal androgen levels, SG-G100 and sGnRH elicited 2-fold increases in plasma androgen levels. The stimulatory effects of sGnRH, but not SG-G100, were abolished in hypophysectomized fish. These results indicate a functional hypothalamic-pituitary-testicular axis in this species, the components of which vary in sensitivity during the annual reproductive cycle in a manner consistent with the observed cycle of plasma steroids of this species.

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A comparison of prolactins from a marine, an estuarine, and a freshwater teleost

Cited by 14 publications

References 31 publications

Evidence of GnRH receptors in cultured pituitary cells of the winter flounder (Pseudopleuronectes americanus W.)

Evidence of GnRH receptors in cultured pituitary cells of the winter flounder (Pseudopleuronectes americanus W.)

Purification and biological characterization of chinook salmon prolactin

Response of male brown bullhead catfish, Ictalurus nebulosus lesueur, to gonadotropin‐releasing hormone and gonadotropin

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