Isolation and characterization of chum salmon growth hormone

The complete amino acid sequence of growth hormone from sturgeon (Acipencer guldenstadti)

The complete amino acid sequence of growth hormone (GH) from a chondrostean species, the sturgeon (Acipencer gludenstaditi), has been determined. Two variants of GH, termed GH I and GH II, were isolated from the pituitary by alkaline extraction, gel filtration on a Sephadex G-100 column, and reversed-phase high-performance liquid chromatography (rpHPLC) on a TSK gel ODS-120T column. The purified proteins were confirmed to be GHs by immunoblotting using bovine and chum salmon GH antisera. For determining of the primary structures, these GHs were digested with lysyl endopeptidase and cleaved with cyanogen bromide. The resulting fragments were separated by rpHPLC and subjected to sequence analysis on an automated gas-phase sequencer employing an Edman method. Both GHs consist of 190 amino acid residues, and contain two disulfide linkages at positions 52-163 and 180-188. The GHs differ from each other at only three positions. Sequence comparison with GHs from other vertebrates revealed that sturgeon GHs have greater sequence homology with tetrapod GHs (63-76%) than with teleost GHs (42-63%).

The complete nucleotide sequence of the Atlantic salmon growth hormone I gene

Two closely related genes encoding growth hormone were isolated from Atlantic salmon by genomic cloning. From one of these genes a total of 6500 nucleotides were determined including 3900 nucleotides in exons and introns and about 600 and 2000 nucleotides in 5' and 3' flanking regions. The gene is organized in six exons and encodes a polypeptide of 210 amino acids including a 22 amino acids signal sequence. The promoter region contains a typical TATA box 21 nucleotides upstream from the transcription start site. At the 3' end, three putative poly(A) signal sequences are present. The last two are within a 121 nt inverted repeat.

Effects of growth hormones on bone formation and resorption in rainbow trout (Oncorhynchus mykiss), as examined by histomorphometry of the pharyngeal bone

Effects of salmon and eel growth hormones (GHs) on bone metabolism in rainbow trout (Oncorhynchus mykiss) were studied using histomorphometry of their pharyngeal bones. When salmon GH (sGH) was injected intraperitoneally at a dose of 0.01 or 0.1 microgram/g/week for 10 times into fed trout, body growth in both length and weight was accelerated. Formation and resorption of bone were enhanced only by the higher dose of sGH. When a cholesterol pellet containing recombinant eel GH (reGH-pellet) was implanted subcutaneously into starved trout for 1 week (37 micrograms reGH/18 g fish), formation and resorption of bone increased, although activity of bone formation was low. The results indicate that the GHs increased both formation and resorption of bone, regardless of the nutritional status of the fish.

Growth hormone binding sites in tilapia (Oreochromis mossambicus) liver

125I-labeled bovine and tilapia growth hormones were used to assess the presence of growth hormone receptors in membranes prepared from tissues of the tilapia Oreochromis mossambicus. The highest level of specific binding was detected in liver membranes from animals of both sexes and the binding was protein-dependent. Tilapia growth hormone, bovine growth hormone, and ovine prolactin, but not tilapia prolactin, potently inhibited the hepatic binding of 125I-labeled bovine growth hormone. Scatchard analysis of the 125I-labeled bovine growth hormone binding data revealed a Bmax (maximum binding) value of 180 fmol/mg protein and a Kd (dissociation constant) value of 13 nM. Tilapia growth hormone potently inhibited hepatic binding of 125I-labeled tilapia growth hormone. Scatchard analysis revealed a single class of binding sites with Bmax and Kd values of 390 fmol/mg protein and 2.5 nM, respectively. Bovine growth hormone and ovine prolactin were less potent while tilapia prolactin was inactive in inhibiting hepatic 125I-labeled tilapia growth hormone binding.

A rapid procedure for the isolation of bioactive growth hormone

A two-step isolation method is described for the purification of growth hormone and prolactin from rat pituitaries. Following alkaline extraction, the sample was chromatographed on Sephadex G-75. Growth hormone and prolactin, which eluted in the same gel filtration fraction, were separated on a reversed-phase HPLC column. The isolated proteins migrated to the same position as rat growth hormone and prolactin standards. Further confirmation that the purified proteins were indeed growth hormone and prolactin was provided by immunoblotting using several mammalian antisera and N-terminal amino acid sequencing. The purified rat growth hormone was shown to be biologically active when tested in the hypophysectomized rat body weight gain assay. Although rat prolactin remains to be tested, it seems likely that this hormone would also have biological activity. The present procedure is of general applicability and particularly useful when only small amounts of pituitary glands are available for extraction.

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. The 42K Mr region yielded two forms of GH, which differ in terms of quantity and net charge as evidenced by native PAGE, a major variant with a relative mobility of (Rf) 0.22 and a lesser variant with Rf 0.28. The less than 33 Mr region has a single GH species with Rf 0.22. Upon sodium dodecyl sulfate-PAGE, without reduction, both GH variants from the 42K Mr region gave Mrs of 21K, while the GH from the less than 33K Mr region was 20K Mr, typical of monomeric vertebrate GHs. The proteins composing the 42K Mr region are proposed as GH dimers since they yield 21K Mr peptides. The less than 33K Mr region contains a GH monomer (20K Mr) in its native state. An amino-terminal amino acid sequence, identical for both the 42K and the 20K Mr Rf 0.22 forms, has good homology with other complete fish GH sequences near their carboxyl-terminal regions (between amino acids 130 and 196). The GH dimers (42K Mr) predominate in the plaice pituitary, contributing 93% of the total, of which 86% gives rise to the Rf 0.22 variant.

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. were used to confirm the isolation of sockeye salmon GH (ssGH). The bioassay was sensitive to a dose of 55 ng of purified ssGH/g fish. Monomeric GHs, located in the carbohydrate-poor protein fraction, were the only pituitary components that elevated serum T3. Twenty-four hours after GH injection was an appropriate and practical time to blood sample, allowing completion of the bioassay, including RIA, in 3 days. The generic homology, between the source of pituitaries and the bioassay animals used in this study, should permit the bioassay to be useful during GH isolation from pituitaries of all Oncorhynchus sp.

Immunoaffinity purification and partial characterization of sea bass (Dicentrarchus labrax) growth hormone

Growth hormone (GH) was isolated from sea bass (Dicentrarchus labrax) pituitary extract by a simple one-step procedure involving immunoaffinity chromatography. A monoclonal antibody raised against chicken GH and found to immunostain very specifically the GH cells in the pituitary of the sea bass was coupled to CNBr-activated Sepharose 4B. Sea bass pituitary extracts were run on the affinity column, and the eluted material was analyzed on reversed-phase HPLC and found to consist of one single peak. The yield of purified hormone was 2.4 mg/g pituitary. Two monomeric forms (MW = 20,000 and 22,000 Da) of sea bass GH were identified by gel electrophoresis. Gel electrofocusing revealed apparent isoelectric points of 6.15, 6.50, and 6.95. Amino acid composition is consistent with other vertebrate GHs. The immunological relatedness was tested by immunoblotting using antisera raised against GH of different species. Polyclonal antisera raised against the isolated hormone exhibited a specific labeling of the GH cells in sea bass pituitary sections as well as of the immunoblotted purified GH.

The complete amino acid sequence of growth hormone of the bullfrog (Rana catesbeiana)

The primary structure of growth hormone (GH) isolated from the adenohypophysis of the bullfrogs (Rana catesbeiana) was determined. The hormone was reduced, carboxymethylated and subsequently cleaved with cyanogen bromide. Intact bullfrog GH was also digested with lysyl endopeptidase and trypsin. The resulting fragments were separated by reverse-phase high-performance liquid chromatography and subjected to sequence analysis using an automated gas-liquid sequencer employing the Edman method. Bullfrog GH was found to consist of 190 amino acid residues. The amino acid sequence determined is in accord with that deduced from bullfrog GH cDNA by Pan and Chang (1988) except for nine residues at positions 43-48, 73, 80 and 87. Sequence comparisons revealed that bullfrog GH is more similar to tetrapod GHs (e.g., 69% homology with sea turtle GH, 66% with chicken GH and 61% with ovine GH) than to GHs of teleosts (e.g., 35% homology with chum salmon GH and 33% with bonito GH) except for eel (52% identity). Bullfrog GH and prolactin exhibit a sequence homology of 25%.

The development of a noncompetitive enzyme-linked immunosorbent assay for oncorhynchid growth hormone using monoclonal antibodies

The development of a sensitive and specific two-site, or sandwich, noncompetitive enzyme-linked immunosorbent assay (ELISA) for oncorhynchid growth hormone (GH) using monoclonal antibodies (MCAs) is reported. The MCAs were generated by the fusion of myeloma cells with spleen cells from mice that had been immunized with chum salmon (Oncorhynchus keta) recombinant GH. The MCAs specifically recognized the GH-secreting acidophils in the proximal pars distalis of immature male rainbow trout (Oncorhynchus mykiss) pituitaries. Affinity chromatography using one of the MCAs isolated a single protein with a molecular weight of 22,500 from a rainbow trout pituitary extract. The ELISA recognized recombinant chum salmon GH and the affinity-purified protein but did not recognize chum salmon prolactin, gonadotropin I or II, nor several mammalian hormone preparations. The ELISA recognized GH in rainbow trout, coho salmon (Oncorhynchus kisutch), and chinook salmon (Oncorhynchus tshawytscha) pituitary extracts, but not in goldfish (Carassius auratus) extracts, and recognized GH in rainbow trout, coho salmon, lake sturgeon (Acipenser fulvescens), and bowfin (Amia calva) plasma, but not in goldfish, yellow bullhead (Ictalurus natalis), or lamprey (Petromyzon marinus) plasma. The sensitivity of the ELISA was less than 1.56 ng/ml and circulating levels of GH in the plasma of coho salmon and rainbow trout plasma were measured as 75 and 35 ng equivalents/ml, respectively.

Distribution and characterization of immunoreactive growth hormone (GH) in the pituitary of the frog Rana ridibunda using an antiserum against purified bullfrog GH

The presence of growth hormone (GH) in the pituitary of the frog Rana ridibunda was investigated using an antiserum raised against purified bullfrog GH. The immunofluorescence technique revealed that GH-containing cells are exclusively located in the dorsal area of the distal lobe of the pituitary. The relative abundance of these GH-positive cells, which correspond to acidophilic type 2 cells, was 18 +/- 1% of the total population of endocrine cells of the pars distalis. Frontal sections of the distal lobe indicated that GH-producing cells are distributed in an arc of a circle occupying all of the dorsal part of the lobe. At the electron microscopic level, GH-immunoreactive material was sequestered in large polymorphic granules (200-700 nm). GH was quantified in R. ridibunda pituitary extracts using a radioimmunoassay for bullfrog GH. The displacement curves obtained with serial dilutions of pars distalis extracts were not strictly parallel to the standard curve made with purified bullfrog GH. In contrast, Western blot analysis revealed that GH from R. ridibunda had a molecular weight (22 kDa) similar to that of bullfrog GH. In the pars distalis, the apparent amount of GH was 0.61 +/- 0.14 microgram per lobe, corresponding to 0.92 +/- 0.17% of total proteins in the extracts. In contrast, frog neurointermediate lobe or hypothalamus did not contain significant concentrations of immunoreactive GH (less than 0.006% of total proteins in the extracts). Taken together, these results validate the use of an antiserum to bullfrog GH to investigate the regulation of GH secretion in R. ridibunda.

The effects of ovine growth hormone on protein turnover in rainbow trout

Ovine growth hormone (oGH) was administered to rainbow trout via an intraperitoneal cholesterol implant. After 21 days, plasma oGH levels were recorded as control group, less than 2 ng ml-1, i.e., not detectable, and oGH group, 19.2 +/- 2.8 ng ml-1. oGH-treated fish exhibited significantly increased whole-body growth rates, whole-body protein accretion rates, stimulated tissue protein synthesis, and tissue protein accretion rates. A dramatic decrease in white muscle protein concentration was also observed after oGH treatment. In some tissues (liver and stomach), elevated protein synthesis rates were the result of higher RNA/protein ratios. However, in other tissues (gill and ventricle), increased RNA activity accounted for the differences in rates of protein synthesis. The growth promoting effects of oGH on both whole-body and tissue protein turnover were generally accompanied with no change in the efficiency of deposition of newly synthesized protein. For the same ration size, the oGH group showed higher retentions of ingested nitrogen. It is concluded that oGH significantly enhances whole-body growth rates as a result of the stimulatory effect on protein synthesis rates with little effect on protein degradation.

Amino acid sequence of growth hormone isolated from medium of incubated pituitary glands of tilapia (Oreochromis mossambicus)

The amino acid sequence of tilapia (Oreochromis mossambicus) growth hormone (GH) was determined directly by Edman degradation of peptide fragments generated by lysyl endopeptidase and trypsin digestion. The N-terminal residue was deduced to be pyroglutamic acid through the use of pyroglutamyl aminopeptidase; its removal allowed amino acid sequence determination of the remainder of the N-terminal trypsin peptide by Edman degradation. Tilapia GH is composed of 187 amino acid residues and shows high similarity to other perciform GHs. Sequence identities are: 89% with tuna GH, 83% with bonito GH, 85% with yellowtail GH, 89% with red sea bream GH, and 34% with bovine GH. The two asparagine residues (Asn-148 and Asn-184) were recovered by Edman degradation, suggesting the absence of N-glycosylation.

Presence of specific growth hormone binding sites in rainbow trout (Oncorhynchus mykiss) tissues: characterization of the hepatic receptor

The present work outlines the presence of specific binding for chinook salmon growth hormone (sGH) in different tissue preparations of rainbow trout. Optimal incubation conditions (pH, Tris, MgCl2) were determined. Specific binding was very sensitive to salt concentration during incubation. The specific binding reached a plateau after 15 and 25 hr of incubation at 12 and 4 degrees. At 20 degrees, specific and nonspecific binding were not stable. Specific binding dissociation was slower than association and was only partial. The binding was saturable (Bmax = 187 +/- 167 pmol), of high affinity (Ka = 2.4 +/- 0.8 10(9) M-1), and very specific for GH, properties which are in agreement with the characteristics of hormonal receptors. Sea bream and mammalian GH appeared 2- and 30-fold, respectively, less potent than cold sGH2 for displacing 125I-sGH2. Tissue preparations from ovary, testis, fat, skin, cartilage, gill, blood pellet, brain, spleen, kidney, and muscle showed significant saturable binding.

The complete amino acid sequences of two variants of growth hormone from Atlantic cod (Gadus morhua)

The complete amino acid sequences of two variants of cod growth hormone (GH) have been determined. The GHs, which have apparent molecular weights of 20K and 22K in SDS-PAGE, consist of 185 amino acids and have calculated molecular weights of 20,733 and 20,805, respectively. Comparison of the two sequences showed only one amino acid difference between the variants, with Lys at position 151 in the 22K GH changed to Gly in the 20K GH. The substitution of a charged amino acid by one which contains no sidechain might be expected to be reflected in the isoelectric point of the molecule. However, the observed pI for both the 20K and 22K GHs was 5.8. The difference in apparent molecular weights by SDS-PAGE suggests the existence of a conformational difference between the variants which is attributable to the observed substitution. This conclusion is in agreement with our previous data obtained from radioimmunoassay studies where the 20K GH shows only 25% cross-reactivity in an assay developed for the 22K GH. Alignment of the cod GH sequence with those of other teleost GHs reveals cod GH to be most similar to advanced marine fish such as tuna, sea bream, bonito, and yellowtail (76-83% identity), whereas it is 62-66% identical to flounder and chum salmon GH.

Molecular cloning and sequencing of Australian black bream Acanthopagrus butcheri and barramundi Lates calcarifer fish growth hormone cDNA using polymerase chain reaction

The complementary DNA (cDNA) encoding the preprotein growth hormone (pre-GH) from two Australian marine fish species, namely Acanthopagrus butcheri and Lates calcarifer, have been isolated, cloned and sequenced. The sequences were amplified from reverse transcribed total RNA of whole brains using Polymerase Chain Reaction (PCR) and oligonucleotide primers corresponding to the 5' and 3' regions of Pagrus major. Use of PCR offers a rapid method of isolating fish GH cDNA sequences for commercial and taxonomic applications. Sequence comparison indicates a high degree of conservation for GH cDNAs within the family Sparidae.

Nucleotide sequence of the complementary DNA for turkey growth hormone

Near-full length complementary DNA (cDNA) clones encoding turkey growth hormone (GH) have been isolated from a pituitary library. The longer of the two turkey GH cDNA clones that were sequenced is 803 base pairs (bp) in length and contains 41 nucleotides of the 5'-untranslated region (UTR), an open reading frame of 648 bp that encodes a 25 amino acid leader polypeptide segment as well as a 191 amino acid mature turkey GH protein, and a 3'-UTR that is 92 bp long followed by a 22 bp poly A tract. Comparison of the turkey GH nucleotide sequence to that of other avian GH clones shows the coding region to be greater than 93% homologous while the homology to mammalian GH sequences is between 68 and 78%. Northern blot analysis showed an approximate 800 bp turkey GH processed mRNA transcript that hybridized to the turkey GH cDNA probe. A large up-regulation of turkey GH transcription occurred when intact cultured pituitaries were treated with 1 nM human growth hormone releasing hormone but only modest changes were observed when cultures were treated with thyroid releasing hormone or somatostatin.

Development and validation of a competitive enzyme immunoassay for chum salmon prolactin: a comparison to radioimmunoassay

An enzyme immunoassay (EIA), based on a competitive assay system, for the measurement of prolactin (PRL) in the pituitary of salmonid fishes and of hormone released in medium from incubated pituitary was developed using a rabbit antiserum to chum salmon PRL (PRL, a combination of PRL I and PRL II). Chum salmon PRL was coupled to horseradish peroxidase (HRP). The incubation procedure for the antigen-antibody reaction was analogous to that in the radioimmunoassay (RIA) for PRL. The antibody-bound HRP-PRL was separated by a double antibody method. The enzyme activity in the precipitate was followed by a colorimetric method, in which 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and o-phenylenediamine were used as substrates. PRL, PRL I, and PRL II showed exactly the same competitive curves in the EIA system. PRL (127-158) showed the highest cross-reactivity among the fragments of PRL examined. Low cross-reactivity was seen with other hormones isolated from chum salmon pituitary. The displacement curves for pituitary extracts from several salmonids, including chum salmon, coho salmon, and rainbow trout, were parallel to that of the PRL standard, whereas those from the carp and tilapia showed negligible cross-reactivity. A parallel displacement curve to the PRL standard was also seen with incubation medium of the pars distalis of the chum salmon pituitary. Plasma from chum salmon, coho salmon, and rainbow trout gave nonspecific HRP activity in the EIA. The values of PRL-EIA were significantly correlated (y = 0.99x + 1.06, r = 0.942, P less than 0.05, n = 24) with those obtained in PRL-RIA.(ABSTRACT TRUNCATED AT 250 WORDS)

The complete amino acid sequence of prolactin from the sea turtle (Chelonia mydas)

The complete amino acid sequence of prolactin (PRL) from a reptile, the sea turtle (Chelonia mydas), was determined for the first time. Sequence analysis was performed on fragments obtained from cleavage of intact and performic acid-oxidized hormone with lysyl endopeptidase, Staphylococcus aureus protease, and o-iodosobenzoic acid employing manual Edman degradation. The sea turtle PRL consists of 198 amino acid residues with three disulfide linkages formed between residues 4-11, 58-173, and 190-198 and possesses heterogeneity indicated by four replacements at positions 55, 145, 148, and 171. Sequence comparison with other vertebrate PRLs revealed that the degree of sequence identity conforms well to expectations based on phylogeny except for the rodent PRLs; sea turtle PRL has 86% identity with chicken PRL; 81% with horse, pig, and fin whale PRLs; 75-71% with cattle, sheep, and human PRLs; 60-56% with mouse and rat PRLs; and 35-31% with carp, salmon, and tilapia PRLs.

Separation of rainbow trout (Salmo gairdneri) growth hormone by gel electrophoresis

Pituitaries from immature (n = 12) and mature female (n = 15) rainbow trout were cultured separately in vitro and subjected to polyacrylamide gel electrophoresis. Four protein bands were identified from the immature rainbow trout and three from the adults. The material from the immature trout was used to raise antisera. Three of the bands, including those with the highest (0.74) and lowest (0.27) Rf values, produced antibodies. Immunocytochemical studies revealed that all of the antisera bound strongly to the growth hormone cells and weakly, if at all, to prolactin cells in pituitary sections from rainbow trout.

Purification and characterization of Atlantic salmon growth hormone and evidence for charge heterogeneity

Highly purified growth hormone (GH) has been isolated from Atlantic salmon (Salmo salar) pituitaries by extraction with acid acetone, acidic precipitation, and reversed-phase high-performance liquid chromatography (HPLC). The yield was 2.5 mg/g wet tissue. The Atlantic salmon GH (sGH) emerged as a single symmetrical peak after HPLC on a reverse phase C18 column. SDS-gel electrophoresis revealed only one band with an estimated molecular weight of 23,000. Atlantic sGH showed a uniform molecular weight, but two-dimensional (2D) gel electrophoresis of the purified sGH revealed charge heterogeneity with pI's ranging from 6.5 to 8.2. Treatment of the purified sGH with alkaline phosphatase concentrated these different forms into a single more alkaline position (pI 8.2) indicating removal of acidic groups. These results were documented using both silver- and immunostaining of the 2D SDS gels. The purified sGH was phosphorylated in vitro by a calmodulin-dependent protein kinase. Phosphorylation of sGH may be a post-translational modification resulting in several molecular forms with variable acidity. Analysis of the amino acid composition of Atlantic sGH revealed homology with GHs isolated from other teleost species and the amino-terminal sequence showed only three different amino acids within the first 25 residues compared to GH isolated from chum salmon (Oncorhynchus keta) and coho salmon (Oncorhynchus kisutch) pituitaries. Atlantic sGH had a methionine as the amino-terminal residue. Antibodies against chum sGH cross-reacted with Atlantic sGH. Antibodies against either Atlantic or chinook (Oncorhynchus tschawytscha) salmon prolactin or human GH did not cross-react with Atlantic sGH. Atlantic sGH was shown to have a slight growth-promoting activity in the rat tibia assay.

The development of monoclonal antibodies against salmon (Oncorhynchus kisutch and O. keta) pituitary hormones and their immunohistochemical identification

Monoclonal antibodies (MCAs) directed against several salmon pituitary hormones were generated by the fusion of myeloma cells with spleen cells from mice that had been immunized with either chum salmon (Oncorhynchus keta) growth hormone (GH) or prolactin (PRL), or one of two purified protein preparations from coho salmon (O. kisutch) pituitaries. Hybridoma were cloned by limiting dilution and screened for MCA production using immunohistochemical procedures. MCAs were generated that bound specifically to GH, PRL, or gonadotropic cells. MCAs were generated that bound to either fine granular material or large globular inclusions in the cytoplasm of the "classical" strongly PAS-positive globular gonadotropic cell type found in mature fish. This suggests that these MCAs are directed against gonadotropin II (GTH II). A MCA was also generated that bound both granular and globular material in the globular gonadotrops and granular material in the weakly PAS-positive vesicular gonadotrops in pituitaries from mature fish and to a cell type in immature rainbow trout pituitaries which is tentatively identified as the gonadotropin I (GTH I) cell type. This MCA did not bind to thyrotrops in immature rainbow trout pituitaries.

Isolation and characterization of recombinant eel growth hormone expressed in Escherichia coli

To obtain information about the microheterogeneity of recombinant protein, recombinant eel growth hormone II (EGH) analogues expressed in Escherichia coli were isolated and characterized. The modification was classified into three types: monodeamidation of Asn, oxidation of Met and N-terminal formylation. Monodeamidated EGH was isolated by ion-exchange chromatography. The major deamidation site (Asn 147) was determined by peptide mapping using the substrate specificity of trypsin. Oxidized EGH and N-terminal-formylated EGH were isolated by reversed-phase high-performance liquid chromatography. Oxidized EGH was identified by amino acid composition analysis and N-terminal-formylated peptide by mass spectrometry.

Growth hormone-dependent potentiation of gonadotropin-stimulated steroid production by ovarian follicles of the goldfish

The possible involvement of growth hormone (GH) in the regulation of ovarian function in the goldfish was investigated by determining the effects of common carp GH on steroid production by vitellogenic and preovulatory ovarian follicles incubated in vitro. Carp GH acts in a dose-dependent manner to potentiate the actions of common carp gonadotropin (GtH) on the production of 17 beta-estradiol and testosterone by vitellogenic ovarian follicles and the actions of human chorionic gonadotropin (hCG) on testosterone production by preovulatory ovarian follicles. Carp GH alone had no effect on basal steroid secretion by either class of ovarian follicles. Chum salmon GH but not bovine GH also enhanced carp GtH-induced production of 17 beta-estradiol by vitellogenic ovarian follicles. Common carp prolactin had no effects on basal or GtH-stimulated steroid production by vitellogenic or preovulatory ovarian follicles. The actions of carp GH on preovulatory follicles were not apparent when tested with the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine, suggesting that GH may act to enhance either the formation or actions of cAMP. In summary, these data demonstrate that GH has a direct modulatory effect on GtH-stimulated steroid production and suggest that GH may be an important regulator of follicular development in the goldfish.

Effects of recombinant eel growth hormone on the uptake of [35S]sulfate by ceratobranchial cartilages of the Japanese eel, Anguilla japonica

Effects of growth hormone (GH) on the synthesis of mucopolysaccharide by ceratobranchial cartilages of the Japanese eel, Anguilla japonica, were examined by monitoring the in vitro uptake of [35S]sulfate. The [35S]sulfate uptake decreased rapidly to one-third of the initial level during the first 3 days after hypophysectomy, and decreased gradually thereafter. When hypophysectomized eels were injected intramuscularly with recombinant eel GH (2 micrograms/g), the plasma GH concentrations increased maximally after 6 hr, and declined rapidly thereafter. On the other hand, the sulfate uptake increased significantly after 12 hr, and high levels were maintained until 48 hr. The stimulating effect of GH was dose dependent (0.02-2 micrograms/g). However, the addition of eel GH (0.05-5 micrograms/ml) to the culture medium did not affect the sulfate uptake by hypophysectomized eel cartilages, suggesting that the stimulative action of GH on the sulfate uptake by the cartilages is indirect.

The complete amino acid sequences of alpha subunits of chum salmon gonadotropins

The complete amino acid sequences of alpha subunits of chum salmon (Oncorhynchus keta) gonadotropins (GTHs), GTH I and GTH II, were determined. Subunits were separated by reversed-phase high-performance liquid chromatography. Two alpha subunits, I alpha 1 and I alpha 2, were obtained from GTH I, whereas only one alpha subunit was obtained from GTH II. Sequence analysis revealed that GTH I alpha 2 is identical to GTH II alpha, but distinct from GTH I alpha 1. The I alpha 1 and II alpha consist of 95 and 92 amino acid residues, respectively. GTH I alpha 1 has 72% sequence identity with GTH I alpha 2. The two alpha subunits show approximately 65% sequence identity with bovine alpha subunit. This is the first finding of two chemically distinct alpha subunits from one species.

Phosphorylation of chicken growth hormone

The possibility that chicken growth hormone (cGH) can be phosphorylated has been examined. Both native and biosynthetic cGH were phosphorylated by cAMP-dependent protein kinase (and gamma -32P-ATP). The extent of phosphorylation was however less than that observed with ovine prolactin. Under the conditions employed, glycosylated cGH was not phosphorylated. Chicken anterior pituitary cells in primary culture were incubated in the presence of 32P-phosphate. Radioactive phosphate was incorporated in vitro into the fraction immunoprecipitable with antisera against cGH. Incorporation was increased with cell number and time of incubation. The presence of GH releasing factor (GRF) increased the release of 32P-phosphate labelled immunoprecipitable GH into the incubation media but not content of immunoprecipitable GH in the cells. The molecular weight of the phosphorylated immunoreactive cGH in the cells corresponded to cGH dimer.

Isolation and characterization of a novel growth hormone cDNA from chum salmon (Oncorhynchus keta)

A cDNA clone which codes for a novel growth hormone has been isolated from the library of chum salmon pituitaries. The clone encodes a polypeptide of 210 amino-acid residues including 22 amino-acid residues of signal peptide, which is identical in length with known chum salmon growth hormone. In the coding region, there are 30 base substitutions, some of which result in 12 amino-acid substitutions. There are 8 base changes in the 5' untranslated region, and large insertions/deletions are in the 3' non-coding region. These results clearly indicate that there are at least two species of mRNAs for growth hormone in chum salmon pituitary.

Partial biochemical and biological characterization of purified chicken growth hormone (cGH). Isolation of cGH charge variants and evidence that cGH is phosphorylated

Chicken growth hormone (cGH) was purified from frozen pituitary glands obtained from recently sacrificed broilers. Glands were homogenized in a protease inhibitor solution (0.5 mM PMSF, 50 KIU/ml aprotinin, pH 7.2); extract was taken to pH 9.0 with calcium hydroxide and the supernatant was differentially precipitated with 20% (fraction A) and 50% (fraction B) ammonium sulfate. cGH (fraction B-DE-1) was obtained in pure form from fraction B after DEAE-cellulose chromatography at pH 8.6, with a yield of 2.9 mg/g tissue. Three charge variants of cGH (Rf = 0.23, 0.30, and 0.35) could be isolated by electroelution after semipreparative nondenaturing polyacrylamide gel electrophoresis of fraction B-DE-1. These charge variants showed the same apparent molecular weight (26,300 Da) by sodium dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions. Isoelectric focusing of fraction B-DE-1 revealed two major components (pI = 7.2 and 7.4) and four minor bands (pI = 6.2, 6.7, 7.1, and 7.5). It was found that fraction B-DE-1 contained a significant amount of esterified phosphate (1 nmol PO4/3.5 nmol protein) similar to that reported previously for ovine GH. The functional integrity of the cGH obtained here was characterized by two heterologous and one homologous bioassays. High activity was shown by fraction B-DE-1 in the tibia assay (1.76 UI/mg) and in the liver ornithine decarboxylase assay (sixfold over control), both made in hypophysectomized rats; and it also stimulated lipolysis (138 and 215% at 10 and 100 ng/ml, respectively) on chicken abdominal adipose tissue explants.

Effects of recombinant human growth hormone and insulin-like growth factor 1 on body growth and blood metabolites in brook trout (Salvelinus fontinalis)

Groups of juvenile brook trout (Salvelinus fontinalis) were acclimated to 12.0-13.0 degrees dechlorified water and a photoperiod of 12 hr light: 12 hr dark. Recombinant human growth hormone (hGH) (10.0 micrograms/g body wt) or insulin-like growth factor 1 (hIGF-1), used in a wide range of dosages (0.001-10.0 micrograms/g body wt), were given weekly as intramuscular injections. The fish receiving hGH were already significantly heavier and longer than the saline-injected control fish after 3 weeks of treatment. In addition, a liver specific growth promoting effect of hGH was found. In contrast, hIGF-1 did not stimulate body growth in any dosage tested. The fish receiving the highest dosages of hIGF-1 were all seriously affected with retarded body growth and high mortality. A possible insulin-like activity of hIGF-1 was verified by measuring the plasma glucose and amino acid levels in brook trout after a single injection of hIGF-1 (2.0 micrograms/g body wt) or bovine insulin (0.01 IU/g body wt). Both hormones caused a reduction in both glucose and amino acid levels to 35% of the control levels 24-72 hr after injection. The results strongly suggest that hIGF-1 does not stimulate growth, but that in high dosages causes profound insulin-like effects in brook trout resulting in hypoglycemia and hypoaminoacidemia.

Cloning of the grass carp growth hormone cDNA

We have constructed a cDNA library in lamda gt11 using mRNA isolated from the pituitary glands of the grass carp (Ctenopharyngodon idellus). Based on the published sequence of the rainbow trout growth hormone cDNA, we synthesized two oligonucleotide probes. One of these hybridized strongly with a specific mRNA fragment from the grass carp pituitary. Using this probe, we have isolated six positive clones carrying an insert of approximately 1.2 Kb. By restriction enzyme digestion, all the clones were determined to be identical. Sequence determination on one of them indicated that it has an open reading frame coding for 210 amino acids. Both the nucleotide and translated amino acid sequence are highly homologous to those of the salmon growth hormone and the common carp. A putative signal peptide consisting of hydrophobic amino acids can be identified at the 5' end of the sequence. A polyadenylation signal, ATTAAA, was also present 12 base upstream from the poly A tail.

Molecular cloning and expression of salmon pituitary hormones

A cDNA library was prepared from chinook salmon pituitaries. Growth hormone (GH), prolactin (PRL) and the β subunit of gonadotropin (GTH) genes were screened using synthetic oligonucleotides as probes. Full size cDNA clones coding for these polypeptide hormones were isolated and characterized. The cDNA sequences for PRL and βGTH have been reported earlier from our laboratories. The cDNA clone for GH contains 1148 bp and codes for a preGH of 210 amino acids. The chinook salmon GH, reported in the present investigation, differs from chum salmon GH in only 1 amino acid, and from coho salmon GH in 5 amino acids. Plasmids containing modified nucleotide sequences coding for GH, PRL and βGTH were constructed individually into an expression vector using the heat-inducible λ pL promotor. Mature PRL, GH and unglycosylated βGTH were expressed in the bacteria at elevated temperature.

Survival of salmonids in seawater and the time-frame of growth hormone action

In salmonids, growth hormone (GH) effectively promotes adaptation of freshwater (FW) fish to seawater (SW), but it has been unclear whether GH has osmoregulatory actions apart from those consequent to an increase in body size. Our objectives were first, to examine the minimum time and dose required for GH to enhance SW adaptation; and second, to optimize the conditions for the acute GH response in developing a convenient GH bioassay based on its plasma ion lowering effect. Trout showed markedly improved SW survival when transferred from fresh water 6, 24, or 48h after a single chum salmon GH injection (0.25 μg/g). Preadapting trout to 1/3 SW enhanced the plasma ion lowering effect of ovine GH (oGH) injected 48h before transfer of the fish to 80% SW. Endogenous plasma GH levels were elevated in control trout switched from low salinities to 80% SW but were depressed in oGH-injected fish after transfer. Under optimal test conditions (1/3 SW preadaptation, 48h pre-transfer injection, and 100% SW final challenge), the reduction in plasma Na(+), Ca(++), and Mg(++) levels of oGH-injected fish was dose-dependent. The oGH doses giving minimum and maximum responses were 50 and 200 ng/g, respectively. In short, GH exerts acute osmoregulatory actions that promote SW adaptation in the absence of changes in body size. Compared with growth GH bioassays, the osmoregulatory assay is superior in economy of time, animal costs, and hormone quantity required and potentially in specificity.

The duality of teleost gonadotropins

The duality of salmon gonadotropins has been proved by biochemical, biological, and immunological characterization of two chemically distinc gonadotropins. GTH I and GTH II were equipotent in stimulating estradiol production, whereas GTH II appears to be more potent in stimulating maturational steroid synthesis. The ratio of plasma levels and pituitary contents of GTHs and the secretory control by a GnRH suggest that GTH I is the predominant GTH during vitellogenesis and early stages of spermatogenesis in salmonids, whereas GTH II is predominant at the time of spermiation and ovulation. GTH I and GTH II are found in distinctly separate cells. In trout, GTH I is expressed first in ontogeny, whereas GTH II cells appear coincident with the onset of spermatogenesis and vitellogenesis, and increase dramatically at the time of final reproductive maturation. Comparison of the amino acid sequences of polypeptides and the base sequences of cDNA revealed that salmon GTH I β is more similar to bovine FSHβ than bovine LHβ and salmon GTH II β shows higher homology to bovine LHβ than to bovine FSHβ. The existence of two pituitary gonadotropins in teleosts as well as tetrapods suggests that the divergence of the GTH gene took place earlier than the time of divergence of teleosts from the main line of evolution leading to tetrapods.

Evolutionary implications of two rainbow trout growth hormone genes

The primary structures of two rainbow trout growth hormone mRNAs (GH1 and GH2) have been deduced by direct sequencing of their respective cDNA clones and portions of the mRNA. Both GH1 and GH2 mRNA contain open reading frames comprised of 630 nucleotides and encode 210 amino acid residues of which 11 are variant. The translated regions of both mRNA are flanked by a short but rather conserved 5'-end, and a relatively long but highly diverged 3'-end. The differences at translated and 3'-untranslated regions suggest that the GH1 and GH2 mRNA originate from different loci. The GH1 and GH2 mRNA are likely transcribed from two distinct loci which were duplicated during tetraploidization of salmonid genome between 50 to 100 million years ago.The GH2 gene has been isolated and sequenced from a rainbow trout genomic library. This gene spans a region of approximately 4 kilobases. The trout GH gene is comprised of 6 exons and 5 introns, in contrast to 5 exons and 4 introns in mammals. The additional intron in the trout gene interrupts the translated regions that are analogous to the last exon of the mammalian counterpart. The alleged internally repeating sequences in mammalian GH, prolactin (Pr1) and placental lactogen (PL) are not observed in the predicted polypeptide sequence of trout GH. In addition, direct repeats that flank exons I, III and V of mammalian GH, Pr1 and PL genes are absent in trout gene. These findings indicate that the rainbow trout GH gene structure does not support the current hypothesis that internally repeated regions in GH, Pr1 and PL arose from a small primordial gene.

Purification of chinook salmon (Oncorhynchus tshawytscha) GH for receptor study

A method for the purification of chinook Salmon (Oncorhynchus tshawytscha) GH, which retains its biological activity, is described. The biological activity was investigated with an established radioreceptor assay using liver membranes from pregnant rabbits and bovine GH as standard and labelled hormone. The enrichment of the preparation was checked with electrophoresis (SDS-PAGE). Extraction and further steps were carried out using low molarity alkaline buffer (pH 8-10, M = 100 mM). Three chromatography steps were performed (Concanavalin-A sepharose, Bio-gel P60, DEAE). Ion exchange chromatography was performed under isocratic conditions (using a 50 cm column). Two isoforms (sGH1 and sGH2) were isolated. The purification yield is 0.7% compared to lyophilized pituitaries. The molecule is homogeneous in SDS-PAGE. Contamination by prolactin, gonadotrophin and corticotrophin is negligible (< 0.5%). It could be demonstrated that the biological activity of the preparation is maintained since this preparation stimulates the growth of juvenile trout (Salmo gairdneri) and binds specifically (35%) to trout liver membranes.

The complete nucleotide sequence of the growth-hormone gene from Atlantic salmon (Salmo salar)

We report here the complete genomic nucleotide sequence for the Atlantic salmon growth-hormone gene (asGH), including 600 bp of 5' flanking sequences. The primary transcription (3651 nt) is significantly longer than that of the mammalian genes, mainly because of larger intron sizes, but also because the asGH gene contains an additional intron (intron 5). The coding regions of the asGH gene have been compared to the corresponding regions from rainbow trout (cDNA and genomic), coho salmon (cDNA) and chum salmon (cDNA). With the exception of the rainbow trout cDNA sequence, all results were in agreement with current classification of the four species. The results of a similar comparison with the mRNA leader and trailer regions were also consistent with current classification. Sequences upstream from the transcription start point have been compared to the corresponding regions from rainbow trout and mammalian GH gene (maGH) upstream sequences. The results showed that the upstream sequences in the two fish species were very similar, while short stretches similar to conserved upstream sequences in the maGH genes were also found. Some of these conserved sequences are known to be involved in the specificity of expression of the mammalian genes.

Purification and characterization of bullfrog growth hormone

A highly purified growth hormone (GH) was isolated from an unadsorbed fraction obtained by subjecting acid acetone extract of bullfrog pituitary glands to DEAE-cellulose column chromatography, a side fraction obtained during the purification of prolactin, by cation-exchange chromatography on CM-Toyopearl and high-performance liquid chromatography on ODS with a yield of 5.6 mg/g protein of the starting material. Intraperitoneal injections of GH to hypophysectomized Xenopus resulted in a considerable elevation of chondroitin sulfate synthesis in the xiphisternal cartilage as measured in vitro. The bullfrog GH had a molecular weight of 22,000 Da as determined by sodium dodecyl sulfate-gel electrophoresis. The isoelectric point of bullfrog GH was estimated to be 7.8 by gel electrofocusing. The partial amino acid sequences of bullfrog GH at both terminal regions were determined.

Molecular cloning and characterization of two forms of trout growth hormone cDNA: expression and secretion of tGH-II by Escherichia coli

We constructed a cDNA library using mRNA isolated from rainbow trout pituitaries. Two types of cDNA clones encoding growth hormone (GH) were isolated and their complete nucleotide sequences determined. Twenty seven nucleotide substitutions in the coding region and 108 in the noncoding region distinguish the cDNAs of trout GH-I and II. Both cDNAs encode polypeptides of 210 amino acids, including a putative signal peptide of 22 amino acids, which differ by 12 residues. In both trout and salmon, GH-I mRNA is predominant, which suggests that the variation in the amount of secreted GH originates from a transcriptional event. Moreover, comparison of rainbow trout and chum salmon GH reveals that, in both cases, the predominant GH-I has mutated less than its GH-II counterpart. Mature tGH-II was expressed in Escherichia coli using the pIN-III-ompA-Hind secretion vector.

Relationship between serum growth hormone levels and the brain and pituitary content of immunoreactive somatostatin in the goldfish, Carassius auratus L

In this study, the relationships between endogenous brain and pituitary immunoreactive somatostatin (irSRIF) and circulating growth hormone (GH) levels in the goldfish were examined using two approaches. First, the amount of irSRIF in extracts of the pituitary gland and various brain regions was measured by radioimmunoassay several times throughout the year and was compared to serum GH levels at each time. The amounts of irSRIF in extracts of the pituitary gland, hypothalamus, and telencephalon were found to be inversely related to seasonal changes in serum GH levels, such that irSRIF was highest in these regions when serum GH levels were lowest (November and February). Conversely, irSRIF in these regions was lower in May, June, and July when serum GH levels were highest. These results suggest that endogenous irSRIF in the pituitary and forebrain may participate in the regulation of seasonal changes in serum GH levels in the goldfish. In extracts from other brain regions (thalamus + midbrain and cerebellum + medulla), some changes in the amount of irSRIF were observed among the various sample times, but these variations were not related to changes in serum GH levels. In a second set of experiments, the origin of irSRIF fibers innervating the goldfish pituitary gland was examined by using brain lesioning techniques to destroy regions of the forebrain known to contain irSRIF perikarya and fibers, and subsequently measuring the amount of irSRIF in the pituitary gland. Lesions in the preoptic area of the forebrain resulted in increased serum GH levels concomitant with a decrease in pituitary irSRIF content. This provides direct evidence that the preoptic area is the origin of a somatostatinergic projection inhibiting GH secretion from the goldfish pituitary. Lesions centered in the nucleus lateral tuberis (NLT) pars anterioris did not influence serum GH levels or the pituitary content of irSRIF. In contrast, more posterior lesions centered in the NLT pars posterioris (NLTp) resulted in a dramatic reduction in the amount of irSRIF in the pituitary. This suggests that the majority of irSRIF projections to the goldfish pituitary pass through the area destroyed by the lesion centered in the NLTp; it is also possible that perikarya within this area may be the origin of at least some of the irSRIF-containing fibers in the goldfish pituitary. Together, results from the present study provide evidence of a functional relationship between circulating levels of GH and endogenous brain and pituitary irSRIF in the goldfish.

Purification of carp growth hormone and cloning of the complementary DNA

The growth hormone (GH) was isolated and purified from common carp (Cyprinus carpio) pituitary glands by salt precipitation and HPLC on reverse-phase C18 columns. The carp GH cDNA was synthesized and cloned in Escherichia coli using EcoRI linkers and pBR322 as vector. The positive clones were selected and sequenced. The full-length carp GH cDNA contains 1187 nucleotide basepairs with an open reading frame coding for the precursor form carp GH of 210 amino-acid residues. The partial amino-acid sequence from the protein completely agrees with that derived from the cDNA, with serine as the first residue in mature carp GH preceded by a 22-residue hydrophobic signal peptide. Comparison of the amino-acid sequence of carp GH with those of various species reveals positional identity at 32.4%, 38.8%, 42.0%, 37.2%, 66%, 55% and 49% with GHs of man, rat, duck, bullfrog, salmon, tuna and yellow tail, respectively.

The complete amino acid sequence of growth hormone from the sea turtle (Chelonia mydas)

The complete amino acid sequence of growth hormone (GH) from a reptilian species (the sea turtle, Chelonia mydas) has been determined for the first time. The hormone was reduced, carboxymethylated, and subsequently cleaved in turn with cyanogen bromide and Staphylococcus aureus protease. The intact protein was also cleaved with lysyl endopeptidase and o-iodosobenzoic acid. The resulting fragments were exclusively separated by reversed-phase high-performance liquid chromatography and subjected to sequence analysis by automated gas-phase sequencer employing the Edman method. The sea turtle GH consist of 190 amino acid residues with two disulfide linkages formed between residues 52-160 and 180-188, and possesses a microheterogeneity, indicated by the presence or absence of an additional alanine residue at the N-terminus. Sequence identities of sea turtle GH to other species of GH are 89% with chicken GH, 79% with rat GH, 68% with blue shark GH, 58% with eel GH, 59% with human GH, and 40% with a teleostean GH such as chum salmon. On the basis of amino acid sequence comparisons, a molecular phylogenetic tree is proposed.

The complete amino acid sequence of growth hormone of an elasmobranch, the blue shark (Prionace glauca)

The complete amino acid sequence of growth hormone (GH) from a phylogenetically ancient fish, the blue shark (Prionace glauca), was determined. The shark GH isolated from pituitary glands by U. J. Lewis, R. N. P. Singh, B. K. Seavey, R. Lasker, and G. E. Pickford (1972, Fish. Bull. 70, 933-939) was purified by reversed-phase high-performance liquid chromatography. The hormone was reduced, carboxymethylated, and subsequently cleaved in turn with cyanogen bromide and Staphylococcus aureus protease. The intact protein was also cleaved with lysyl endopeptidase and o-iodosobenzoic acid. The resulting peptide fragments were separated by rpHPLC and submitted to sequence analysis by automated and manual Edman methods. The shark GH consists of 183 amino acid residues with a calculated molecular weight of 21,081. Sequence comparisons revealed that the elasmobranch GH is considerably more similar to tetrapod GHs (e.g., 68% identity with sea turtle GH, 63% with chicken GH, and 58% with ovine GH) than teleostean GHs (e.g., 38% identities with salmon GH and 42% with bonito GH) except for eel GH (61% identity), and substantiates the earlier finding derived from the immunochemical and biological studies (Hayashida and Lewis, 1978) that the primitive fish are less diverged from the main line of vertebrate evolution leading to the tetrapod than are the modern bony fish.

Isolation and characterization of growth hormone from Atlantic cod (Gadus morhua)

Growth hormone was purified from cod pituitary extract by a simple two-step procedure involving gel filtration and reversed-phase high-performance liquid chromatography (rpHPLC). At each stage of purification, fractions were monitored by rpHPLC, SDS-polyacrylamide gel electrophoresis, and immunoblotting using anti-chum salmon growth hormone (GH) antiserum. The yield of purified hormone was 1.3 mg/g pituitary. Cod GH was found to exist in two monomeric forms (Mr = 20K and 22K) and dimeric forms (Mr = 40K and 42K). The two monomeric forms have a pI of 5.8, an identical amino acid composition, histidine as the N-terminal residue, and an identical lysyl endopeptidase peptide map. Staining with concanavalin A was observed on the 20K component only, but analysis for total reducing sugar did not confirm these results. Cod GH was found to be a potent stimulator of growth in juvenile rainbow trout which received intraperitoneal injections of the hormone. The partial amino acid sequence has been determined.

Melanin concentrating hormone. II. Structure and biosynthesis of melanin-concentrating hormone

Melanin-concentrating hormone is a neuropeptide produced in teleost hypothalami and transferred to the neurohypophysis. Salmon MCH was a novel cyclic heptadecapeptide capable of inducing melanin aggregation of integumentary melanophores at picoto nano-molar concentrations in all teleosts tested. The MCH gene is intronless and the exon encodes a 132 amino acid precursor protein, in which the heptadecapeptide of MCH locates at the C-terminal end. Immunohistochemical surveys with anti-salmon MCH antiserum strongly suggest that an MCH-like peptide is present in the hypothalami of higher vertebrates. Biological effects of salmon MCH on other vertebrates are found to be versatile.