Effects of long-term temperature acclimation on thyroid hormone deiodinase function, plasma thyroid hormone levels, growth, and reproductive status of male Atlantic cod, Gadus morhua.

The recent collapse of the Northwestern Atlantic cod fisheries has coincided with a cooling of water temperatures. During this time the condition factor of cod has been poor. The objective of the present study was to determine the effects of long-term temperature acclimation on growth reproduction and thyroid function in laboratory held Atlantic cod (Gadus morhua).

Effect of cysteine substitutions on the mitogenic activity and stability of recombinant human keratinocyte growth factor.

Human Keratinocyte growth factor (hKGF), a member of the FGF family of growth factors, contains five cysteines at amino acid positions 1, 15, 40, 102, and 106. We expressed five cysteine mutants of hKGF in which the cysteines were cumulatively replaced with alanine or serine, starting with cysteine-1. Recombinant hKGF has an inherently higher mitogenic activity and stability to heat and acid than reported for glycosylated hKGF.

Gonadotropin action on brook trout sperm duct epithelium: ion transport stimulation mediated by cAMP and Ca2+.

The isolated sperm duct epithelium from the brook trout Salvelinus fontinalis serves as a model for gonadotropin (GtH) action and is the only example of direct GtH stimulation of epithelial ion transport. In response to purified salmonid carbohydrate-rich GtH added to either the luminal or blood side of the epithelium, the duct actively secretes K+ (measured as 86Rb+ fluxes) and actively reabsorbs Na+ (measured by 22Na+ fluxes or as short circuit current, Isc). As a consequence of the ion transport, the seminal plasma has low Na+ concentration and high K+ content that in turn keeps developing sperm quiescent prior to spawning.

Steroids involved with final oocyte maturation in the winter flounder.

A number of androgens and progestogens including 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20-P) were examined in female winter flounder as possible maturation inducing steroids (MIS). During final oocyte maturation serum levels of testosterone (T) and 17 beta-hydroxy-5 beta-androsten-3-one (5 beta-T) peaking at over 200 ng/ml and pregnenolone (PE) at 40 ng/ml were the predominant steroids found from each major group. High levels of T and 5 beta-T were correlated with oocyte stages characterized by germinal vesicle migration.

Growth enhancement in transgenic Atlantic salmon by the use of an "all fish" chimeric growth hormone gene construct.

We have developed an "all fish" growth hormone (GH) chimeric gene construct by using an antifreeze protein gene (AFP) promoter from ocean pout linked to a chinook salmon GH cDNA clone. After microinjection into fertilized, nonactivated Atlantic salmon eggs via the micropyle, transgenic Atlantic salmon were generated. The presence of the transgene was detected by polymerase chain reaction (PCR) using specific oligonucleotide primers.

Isolation of sockeye salmon growth hormone utilizing serum triiodothyronine enhancement in rainbow trout to monitor biological activity.

Growth hormone (GH) was isolated from sockeye salmon (Oncorhynchus nerka) pituitary glands using established techniques of affinity and gel filtration chromatography, and preparative polyacrylamide gel electrophoresis. The GH activity was followed throughout the fractionation procedure with a bioassay based on the increase of serum triiodothyronine (T3) in rainbow trout (Oncorhynchus mykiss), measured by radioimmunoassay (RIA). Amino-terminal amino acid sequence analysis and subsequent comparison with established GH sequences from other Oncorhynchus sp.

Growth hormone heterogeneity in American plaice pituitaries: isolation, characterization, and partial amino acid sequence.

Growth hormones (GHs) have been isolated from pituitary glands of American plaice (Hippoglossoides platessoides), a marine flatfish, using affinity and gel filtration chromatography, followed by preparative polyacrylamide gel electrophoresis (PAGE). A bioassay based on serum triiodothyronine elevation in immature rainbow trout was used to monitor biological activity. These GHs originate from two molecular mass regions, 42K and less than 33K relative molecular mass (Mr), in their native state.

Stimulation of in vitro ovarian estradiol-17 beta synthesis in the rainbow trout by the carbohydrate-poor protein fraction from sockeye salmon pituitary glands.

The role of carbohydrate-poor (Con A I) and carbohydrate-rich (Con A II) pituitary protein fractions, isolated from sockeye salmon (Oncorhynchus nerka), were investigated pertaining to in vitro estradiol-17 beta (E2) production by rainbow trout (Oncorhynchus mykiss) ovarian follicles. During the early vitellogenic phase of the reproductive cycle, using defolliculated ovarian follicle preparations (outer epithelium-thecal layer absent), it was demonstrated that the Con A I fraction was capable of increasing E2 production, in the presence of exogenous testosterone (T) as the substrate. Under similar conditions the Con A II fraction (containing the maturational gonadotropin) was inactive.

Vidalols A and B, new anti-inflammatory bromophenols from the Caribbean marine red alga Vidalia obtusaloba.

Chemical studies of the Caribbean red alga Vidalia obtusaloba have resulted in the isolation of two new bromophenolic metabolites, vidalols A and B (1, 2). The new compounds were discovered as part of an organized effort to isolate new naturally-occurring anti-inflammatory agents with a focus upon those which may function through the inhibition of phospholipase A2.

Transport of 17α,20β-dihydroxy-4-pregnen-3-one in brook troutSalvelinus fontinalis ovarian follicles.

Extremely low levels of the maturation inducing steroid (MIS) 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DHP) were found in the ooplasm and ovarian follicle membranes of Atlantic salmonSalmo salar ouananiche, a finding that is at variance with the elevated blood levels of the steroid. The uptake of MIS at physiological concentrations into brook trout follicles occurred by passive diffusion. Uptake of the steroid into the ovarian follicle membrane, consisting of zona radiata and the attached follicle cells, deviated from linearity in a double reciprocal plot.

Demonstration of putative membrane and cytosol steroid receptors for 17α, 20β-dihydroxy-4-pregnen-3-one in brook troutSalvelinus fontinalis oocytes by photoaffinity labelling using synthetic progestin 17,21-dimethyl-19-nor-pregn-4,9-diene-3,20-dione (R5020).

Cytosol from brook trout ovarian follicles (stages 1-3) was photoaffinity (PA) labelled using synthetic progestin 17,21-dimethyl-19-nor-pregn-4,9-diene-3,20-dione ([(3)H]R5020). The covalently bound cytosol protein had a relative mass of 501,000 Mr following Sephacryl S-300 column chromatography. The zona radiata membrane fraction from brook trout oocytes which had gone through the first phase of meiotic maturation (stages 6-7) was isolated by ultracentrifugation of the whole oocytes.

Gonadotropin stimulation of K+ secretion and Na+ absorption by brook trout (Salvelinus fontinalis) sperm duct epithelium.

The sperm duct epithelium from mature spermiating brook trout (Salvelinus fontinalis) was mounted in vitro to examine control of Na+ absorptive and K+ secretory transport. Na+ absorption (measured as the short-circuit current) and K+ secretion (measured using 86Rb+ as tracer) were stimulated by 3-isobutyl-1-methylxanthine and cyclic AMP while unstimulated tissues had no net ion transport. Purified chum salmon (Oncorhynchus nerka) Con AII carbohydrate-rich gonadotropin produced a rapid, sustained rise in Rb+ secretion and Na+ uptake in a log linear dose-dependent manner.

Hormonal regulation of antifreeze protein gene expression in winter flounder.

The essential features of experiments carried out over the past fifteen years are brought together with new data to formulate a model describing the hormonal regulation of the annual plasma antifreeze polypeptide (AFP) cycle in winter flounder (Pseudopleuronectes americanus). The precise time of onset of antifreeze synthesis in the fall appears to be regulated by photoperiod acting through the central nervous system (CNS) on the pituitary gland. During the summer, growth hormone (GH) blocks transcription of the AFP genes.

Control of ion transport by the sperm duct epithelium of brook trout (Salvelinus fontinalis).

The sperm duct epithelium of brook trout (Salvelinus fontinalis), mountedin vitro in Ussing-style epithelial chambers actively absorbs Na(+) (measured as the short-circuit current, Isc) and secretes K(+) (measured using(86)Rb(+) as tracer). Dibutyryl-cyclic-adenosine monophosphate (db-cAMP) and 3-isobutyl-1-methylxanthine (IMX) produce a rapid, sustained stimulation of both ion transport processes, but the hormone connected to the response is unknown. Purified sockeye salmon CON A2 gonadotropin (GtH) produces a dose-dependent, rapid and sustained rise in Na(+) uptake and K(+) secretion.

Regulation of antifreeze protein production in winter flounder: a unique function for growth hormone.

Salmon pituitary extract and the protein fraction unabsorbed on concanavalin A-Sepharose, the carbohydrate-poor fraction, depressed plasma levels of antifreeze proteins (AFP) when the pituitary fractions were administered to flounder in late fall or winter. The active pituitary protein occurred in the fraction with a mean molecular weight of 25,000. The two major isohormones of growth hormone (GH) were the only biologically active proteins identified from the pituitary.

The presence of 17α,20β-dihydroxy-4-pregnen-3-one receptor activity in the ovary of the brook trout,Salvelinus fontinalis, during terminal stages of oocyte maturation.

The presence of 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DHP) oocyte receptor activity has been demonstrated in brook troutSalvelinus fontinalis. Scatchard analyses of the cytosol fraction during various terminal stages of oocyte maturation gave a high equilibrium association constant (Ka) value of 1.394±0.

Molecular cloning and expression of salmon prolactin cDNA.

Prolactin was purified from chum salmon pituitaries. It was resolved into two variants by reverse-phase high-performance liquid chromatography. A cDNA library was prepared from Pacific chinook salmon pituitaries.

Adrenocorticotropin- and opiate-like hormones from pituitaries of the sockeye salmon Oncorhynchus nerka.

The pituitaries of vitellogenic sockeye salmon (Oncorhynchus nerka) were extracted with a mixture of acetone, water, and hydrochloric acid. The precipitate which formed upon the addition of a copious volume of acetone to the extract, designated acid acetone powder, was subjected to salt fractionation and desalting, followed by ion-exchange chromatography on CM-cellulose. An unadsorbed fraction (S-1) and four adsorbed fractions (S-2, S-3, S-4 and S-5) were obtained.

The cellular location of 1 alpha-hydroxycorticosterone binding protein in skate.

Antiserum to 1 alpha-hydroxycorticosterone binding protein was used to investigate its location in selected tissues of the skate Raja ocellata. Immunofluorescence, using an indirect technique, showed 1 alpha-hydroxycorticosterone binding sites in potential target tissue: gill. chloride cells, rectal gland parenchyma, and a portion of the kidney tubule.

Maturational steroids and gonadotropin in upstream migratory sockeye salmon.

The circulating serum concentrations of various steroid hormones in mature sockeye salmon were measured at four different developmental stages in their upstream migration to spawn at Adams River in British Columbia, Canada. In females, a high level of estradiol-17 beta was found in fish at the first location, and it persisted until immediately before reaching the spawning grounds, 485 km upstream, where it decreased to a minimal level. Free testosterone was extremely high throughout the migration but decreased significantly after spawning while its glucuronide changed reciprocally.

Progestogens, androgens and their glucuronides in the terminal stages of oocyte maturation in landlocked Atlantic salmon.

Peripheral serum levels of free and conjugated steroids were correlated with seven terminal stages of oocyte maturation in female landlocked Atlantic salmon. Pregnenolone levels were maximal at stage 1, and there was a surge in testosterone after initiation of germinal vesicle migration. Testosterone remained high, above 25 ng/ml until ovulation, and its glucuronide was always lower than the corresponding free form.

Epidermal cellular proliferation and differentiation in sexually mature male Salmo salar with androgen levels depressed by oil.

Sexually mature male Salmo salar exhibit epidermal thickening and an increase in goblet cell concentration during the spawning season. The ventral skin, which is likely to experience most abrasive contact during the spawning period, has the thickest epidermis and the greatest goblet cell concentration. Following exposure to crude oil there is inhibition of cellular proliferation and elongation associated with epidermal thickening, and also inhibition of mucigenesis.