Search Results
You are looking at 1 - 7 of 7 items for
- Author: P Swanson x
- Refine by access: All content x
Search for other papers by A. P. PAYNE in
Google Scholar
PubMed
Search for other papers by H. H. SWANSON in
Google Scholar
PubMed
SUMMARY
Male golden hamsters received either 300 μg testosterone propionate or oil on day 1 of life. As adults they were observed (i) when intact (ii) when castrated and (iii) when receiving 1 mg testosterone propionate per day in interactions with intact dioestrous females. Male controls which had received oil neonatally resembled normal untreated males in showing less aggressive behaviour than females. Castration and subsequent androgen administration did not affect aggression in the controls. Conversely, neonatally androgenized males showed comparable levels of aggression to the females with which they interacted. Castration reduced aggressive behaviour in these males, while subsequent androgen administration resulted in them showing significantly more aggression than females. In particular, when intact or receiving androgen replacement, neonatally androgenized males attacked and bit females, a behaviour seldom seen in normal males or in those given oil neonatally. Sexual investigation and following decreased in both groups of males after castration, and increased under androgen replacement. These changes were more pronounced in the neonatally androgenized males, indicating a greater behavioural responsiveness to androgens in this group. It is suggested that the behaviour of the normal male hamster is incompletely 'masculinized' during neonatal development, and the possible adaptive significance of this is discussed.
Search for other papers by A. P. PAYNE in
Google Scholar
PubMed
Search for other papers by H. H. SWANSON in
Google Scholar
PubMed
There is considerable evidence that androgens facilitate the display of aggression in male vertebrates, while ovarian steroids do not (e.g. Guhl, 1961; Suchowsky, Pegrassi & Bonsignori, 1969). The golden hamster is unusual in that both sexes are aggressive, the female being dominant over the male (Dieterlen, 1959; Payne & Swanson, 1970). This study was undertaken to discover whether implanting ovarian tissue into castrated male hamsters influences their aggressive behaviour.
Twenty-eight adult male hamsters were castrated under ether anaesthesia. Simultaneously, in half of these a portion of ovarian tissue, freshly removed from an adult female, was implanted under the right kidney capsule. Six to 7 months later, both groups of castrated animals were tested by placing each animal in a neutral cage with a strange, intact male of the same body weight (± 3 g) for a 10-min observation period on 3 successive days. During each test the behaviour of both
Search for other papers by M. Rand-Weaver in
Google Scholar
PubMed
Search for other papers by P. Swanson in
Google Scholar
PubMed
Search for other papers by H. Kawauchi in
Google Scholar
PubMed
Search for other papers by W. W. Dickhoff in
Google Scholar
PubMed
ABSTRACT
Somatolactin (SL), a newly discovered fish pituitary protein belonging to the GH/prolactin family, was isolated from coho salmon (Oncorhynchus kisutch). Antibodies were raised to purified coho SL, and a homologous radioimmunoassay was developed and validated. The assay was specific for SL as indicated by the absence of cross-reactivity with coho salmon GH, gonadotrophins I and II and less than 0·2% cross-reaction to prolactin. Serial dilutions of plasma and pituitary extracts from Oncorhynchus species including coho salmon, chinook salmon and rainbow trout were parallel to the coho salmon SL standard curve. Displacement curves for dilutions of Atlantic salmon (Salmo salar) plasma, but not pituitary extract were parallel to the standards. Plasma levels of SL were measured in coho salmon throughout the final year of reproductive maturation. During the period of gonadal growth, plasma SL levels increased and were highly correlated to oestradiol levels in females and 11-ketotestosterone levels in males. Peak levels of SL were observed at the time of final maturation and spawning in both sexes. It is hypothesized that SL may regulate some physiological aspect of reproduction.
Journal of Endocrinology (1992) 133, 393–403
Search for other papers by Bauchat JR in
Google Scholar
PubMed
Search for other papers by Busby WH Jr in
Google Scholar
PubMed
Search for other papers by A Garmong in
Google Scholar
PubMed
Search for other papers by P Swanson in
Google Scholar
PubMed
Search for other papers by J Moore in
Google Scholar
PubMed
Search for other papers by M Lin in
Google Scholar
PubMed
Search for other papers by C Duan in
Google Scholar
PubMed
Rainbow trout (Oncorhynchus mykiss) serum contains several IGF-binding proteins (IGFBPs) that specifically bind to IGFs. The structures of these fish IGFBPs have not been determined and their physiological functions are poorly defined. In this study, we identified a 30 kDa IGFBP present in rainbow trout serum and secreted by cultured trout hepatoma cells. This IGFBP binds to IGFs but not to insulin. This IGFBP was purified to homogeneity using a three-step procedure involving Phenyl-Sepharose chromatography, IGF-I affinity chromatography and reverse-phase HPLC. Affinity cross-linking studies indicated that this IGFBP binds to IGF-I with a higher affinity than to IGF-II. N-terminal sequence analysis of the trout IGFBP suggests that it shares high sequence identity with that of human IGFBP-1 in the N-terminal region. When added to cultured fish and human cells, the trout IGFBP inhibited IGF-I-stimulated DNA synthesis and cell proliferation in a concentration-dependent manner. The inhibitory effect of the fish IGFBP was comparable to those of human IGFBP-1 and -4. These results indicate that the IGFBP molecule is structurally and functionally conserved in evolutionarily ancient vertebrate species such as bony fish.
Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand
Northwest Fisheries Science Center, NOAA Fisheries, Seattle, Washington 98112, USA
Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
Search for other papers by M Kusakabe in
Google Scholar
PubMed
Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand
Northwest Fisheries Science Center, NOAA Fisheries, Seattle, Washington 98112, USA
Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
Search for other papers by I Nakamura in
Google Scholar
PubMed
Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand
Northwest Fisheries Science Center, NOAA Fisheries, Seattle, Washington 98112, USA
Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
Search for other papers by J Evans in
Google Scholar
PubMed
Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand
Northwest Fisheries Science Center, NOAA Fisheries, Seattle, Washington 98112, USA
Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
Search for other papers by P Swanson in
Google Scholar
PubMed
Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand
Northwest Fisheries Science Center, NOAA Fisheries, Seattle, Washington 98112, USA
Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA
Search for other papers by G Young in
Google Scholar
PubMed
In vertebrates, sperm development and maturation are directly regulated by gonadal steroid hormone secretion. The relationships among the expression of genes encoding steroidogenic proteins and receptors for gonadotropins, and testicular steroid production have not yet been comprehensively determined in male teleosts. In this study, the changes in levels of mRNAs encoding follicle-stimulating hormone (FSH) receptor, luteinizing hormone (LH) receptor, steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side-chain cleavage, 3β-hydroxysteroid dehydrogenase/Δ5–4-isomerase, cytochrome P450 17α-hydroxylase/17,20-lyase, cytochrome P450 11β-hydroxylase, 11β-hydroxysteroid dehydrogenase and 20β-hydroxysteroid dehydrogenase were determined by real-time, quantitative PCR assays and related to changes in serum steroid levels throughout the reproductive cycle in male rainbow trout. Serum 11-ketotestosterone and 17α,20β-dihydroxy-4-pregnen-3-one levels were measured by RIA. Although the pattern of change in the mRNA levels for the enzymes was variable, the increases in steroidogenic enzyme mRNAs started prior to a significant increase of serum steroid levels. The patterns of transcript levels of FSH and LH receptors suggest that changes in StAR and steroidogenic enzyme transcripts are largely mediated by the FSH receptor during early and mid-spermatogenesis and by the LH receptor during late spermatogenesis and spermiation. Levels of StAR (10-fold) and P450 17α-hydroxylase/17,20-lyase (sevenfold) transcripts changed with the greatest magnitude and were closely related to the changes in serum steroids, suggesting that changes in StAR and P450 17α-hydroxylase/17,20-lyase abundance are likely to be the major influences on overall steroidogenic output during the reproductive cycle in male rainbow trout.
Integrative Fish Biology Program, School of Aquatic and Fishery Sciences, Northwest Fisheries Science Center, National Marine Fisheries Service, 2725 Montlake Boulevard E., Seattle, Washington 98112, USA
Search for other papers by A L Pierce in
Google Scholar
PubMed
Integrative Fish Biology Program, School of Aquatic and Fishery Sciences, Northwest Fisheries Science Center, National Marine Fisheries Service, 2725 Montlake Boulevard E., Seattle, Washington 98112, USA
Search for other papers by J T Dickey in
Google Scholar
PubMed
Integrative Fish Biology Program, School of Aquatic and Fishery Sciences, Northwest Fisheries Science Center, National Marine Fisheries Service, 2725 Montlake Boulevard E., Seattle, Washington 98112, USA
Search for other papers by L Felli in
Google Scholar
PubMed
Integrative Fish Biology Program, School of Aquatic and Fishery Sciences, Northwest Fisheries Science Center, National Marine Fisheries Service, 2725 Montlake Boulevard E., Seattle, Washington 98112, USA
Search for other papers by P Swanson in
Google Scholar
PubMed
Integrative Fish Biology Program, School of Aquatic and Fishery Sciences, Northwest Fisheries Science Center, National Marine Fisheries Service, 2725 Montlake Boulevard E., Seattle, Washington 98112, USA
Search for other papers by W W Dickhoff in
Google Scholar
PubMed
Igf1 and Igf2 stimulate growth and development of vertebrates. Circulating Igfs are produced by the liver. In mammals, Igf1 mediates the postnatal growth-promoting effects of growth hormone (Gh), whereas Igf2 stimulates fetal and placental growth. Hepatic Igf2 production is not regulated by Gh in mammals. Little is known about the regulation of hepatic Igf2 production in nonmammalian vertebrates. We examined the regulation of igf2 mRNA level by metabolic hormones in primary cultured coho salmon hepatocytes. Gh, insulin, the glucocorticoid agonist dexamethasone (Dex), and glucagon increased igf2 mRNA levels, whereas triiodothyronine (T3) decreased igf2 mRNA levels. Gh stimulated igf2 mRNA at physiological concentrations (0.25×10−9 M and above). Insulin strongly enhanced Gh stimulation of igf2 at low physiological concentrations (10−11 M and above), and increased basal igf2 (10−8 M and above). Dex stimulated basal igf2 at concentrations comparable to those of stressed circulating cortisol (10−8 M and above). Glucagon stimulated basal and Gh-stimulated igf2 at supraphysiological concentrations (10−7 M and above), whereas T3 suppressed basal and Gh-stimulated igf2 at the single concentration tested (10−7 M). These results show that igf2 mRNA level is highly regulated in salmon hepatocytes, suggesting that liver-derived Igf2 plays a significant role in salmon growth physiology. The synergistic regulation of igf2 by insulin and Gh in salmon hepatocytes is similar to the regulation of hepatic Igf1 production in mammals.
School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington 98195, USA
Search for other papers by A L Pierce in
Google Scholar
PubMed
School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington 98195, USA
Search for other papers by M Shimizu in
Google Scholar
PubMed
School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington 98195, USA
Search for other papers by L Felli in
Google Scholar
PubMed
School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington 98195, USA
Search for other papers by P Swanson in
Google Scholar
PubMed
School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington 98195, USA
Search for other papers by W W Dickhoff in
Google Scholar
PubMed
IGF-binding proteins (IGFBPs) modulate the effects of the IGFs, major stimulators of vertebrate growth and development. In mammals, IGFBP-1 inhibits the actions of IGF-I. Rapid increases in circulating IGFBP-1 occur during catabolic states. Insulin and glucocorticoids are the primary regulators of circulating IGFBP-1 in mammals. Insulin inhibits and glucocorticoids stimulate hepatocyte IGFBP-1 gene expression and production. A 22 kDa IGFBP in salmon blood also increases during catabolic states and has recently been identified as an IGFBP-1 homolog. We examined the hormonal regulation of salmon IGFBP-1 mRNA levels and protein secretion in primary cultured salmon hepatocytes. The glucocorticoid agonist dexamethasone progressively increased hepatocyte IGFBP-1 mRNA levels (eightfold) and medium IGFBP-1 immunoreactivity over concentrations comparable with stressed circulating cortisol levels (10−9–10−6 M). GH progressively reduced IGFBP-1 mRNA levels (0.3-fold) and medium IGFBP-1 immunoreactivity over physiological concentrations (5 × 10−11–5 × 10−9 M). Unexpectedly, insulin slightly increased hepatocyte IGFBP-1 mRNA (1.4-fold) and did not change medium IGFBP-1 immunoreactivity over physiological concentrations and above (10−9–10−6 M). Triiodothyronine had no effect on hepatocyte IGFBP-1 mRNA, whereas glucagon increased IGFBP-1 mRNA (2.2-fold) at supraphysiological concentrations (10−6 M). This study suggests that the major inhibitory role of insulin in the regulation of liver IGFBP-1 production in mammals is not found in salmon. However, regulation of salmon liver IGFBP-1 production by other metabolic hormones is similar to what is found in mammals.
