Correlation with larval body size of mRNA levels of growth hormone, growth hormone receptor I and insulin-like growth factor I in larval torafugu Takifugu rubripes

Abstract

The full-length of insulin-like growth factor (IGF) complementary (c)DNAs encoded by igf-I and igf-II from torafugu pufferfish Takifugu rubripes were cloned in the present study. The deduced amino acid sequences of the two genes showed c. 80% identity each with those of Igf-I and Igf-II from other teleosts, respectively. Two growth hormone (GH) receptors, ghr1 and ghr2, were also cloned in silico using the T. rubripes Fugu genome database. The transcripts of T. rubripes igf-I were detected in slow muscle, heart, skin, gill, liver and intestine but not in fast muscle, spleen and testis of adult fish, whereas those of igf-II were found in all tissues examined. Subsequently, the accumulated messenger (m)RNA levels of igf-I and igf-II were investigated in an F(2) population derived from a male of an apparent fast-growing T. rubripes strain and a wild female T. rubripes together with those of other growth-related genes encoding Gh, Ghr1 and Ghr2, and with those of prolactin (Prl) and leptin (Lep) previously reported. The accumulated mRNA levels of igf-I, gh and ghr1 were significantly correlated to growth rate at larval stages in the population, but not for those of igf-II, prl, ghr2 and lep. Although it is unclear whether or not this phenotype is directly related to the heredity of the fast-growing strain, the findings suggest that the expression of igf-I, gh and ghr1 is involved in the regulation of growth rate at larval stages in T. rubripes.

Effects of Estradiol and Testosterone on the Expression of Growth‐related Genes in Female and Male Nile Tilapia, Oreochromis niloticus

“…While GHR1 is likely to be a receptor for somatolactin, a pituitary hormone that is unique to teleosts, GHR2 is a receptor for GH (Pierce et al ). The body length of Takifugu rubripes is correlated with the expression of ghr1 and igf1 but not of ghr2 or igf2 (Kaneko et al ). A significant correlation among the expression levels of igf1, igf2 , ghr1 , and ghr2 was observed in this study, suggesting that the effect of GH on IGF s is mediated by GHRs and that GH–GHRs binding is necessary to stimulate IGF1 synthesis and release (Kita and Nagao ).…”

A feedback regulatory loop involving p53/miR-200 and growth hormone endocrine axis controls embryo size of zebrafish

“…Growth hormone is a pituitary hormone that participates in numerous physiological processes including somatic growth and energy metabolism 4 . The elevated expressions of GH/IGF genes have been shown to be positively correlated with faster growth rate in mammalians 5 and aquaculture fish species 6 7 8 9 . Moreover, GH transgenic mouse 5 and aquaculture fish species 10 11 12 show much faster growth rate than the control group.…”

Embryonic arsenic exposure reduces intestinal cell proliferation and alters hepatic IGF mRNA expression in killifish (Fundulus heteroclitus)

“…Since intestinal cell turnover was impaired throughout the life of the fish, yet growth in metal-exposed fish was similar controls, compensatory mechanisms were examined. In fish, IGF-1 directly controls larval (Kaneko et al 2011) and adult fish growth rates (Duan 1998;Reindl and Sheridan 2012). Since liver is the primary organ for IGF-1 synthesis, hepatic IGF-1 and IGF-1 binding protein (IGFBP-1) transcript levels were determined.…”

“…IGF-1 is postulated to be one of the most important modulators of growth in fish (Duan 1998;Kaneko et al 2011;Vélez et al 2018). Szymkowicz et al (2017) previously reported that skeletal muscle IGF-1 transcript levels were elevated in 16, 28, 40, and 52 week old killifish exposed to 200 and 800 ppb As as embryos.…”