The expressions of nka and nkcc in the gill as well as gh/prllbp and igfl in the gill and hepatic caecum were analyzed by qRT-PCR as above.
rGHl Induces Expression of igfl. GHl was shown to be able to regulate growth through IGF action; thus, we tested the effects of rGHl and rzGH on the expression of igfl in the hepatic caecum and gill of amphioxus.
Salinity Increase Induces Expression of ghl, gh/prllbp, and igfl. To test if a vertebrate-like GH-IGF axis is involved in the osmoregulation in amphioxus, we transferred the 25[per thousand] salinity-acclimated animals to seawater with 30[per thousand] salinity and examined the effects of salinity change on the expression of ghl in the Hatschek's pit and gill as well as gh/prllbp and igfl in the hepatic caecum and gill.
In addition, we show that GHl induces upregulation of both the ion transporter NKA and cotransporter NKCC in the gill as well as mediator of GH action IGFl in the hepatic caecum, indicating that GHl apparently fulfills this osmoregulatory activity through the same mechanisms of vertebrate GH.
Zhang, "Expression and regulation by thyroid hormone (TH) of zebrafish IGF-I gene and amphioxus IGFl gene with implication of the origin of TH/IGF signaling pathway," Comparative Biochemistry and Physiology.
Interestingly, candidate genes mapping near some of these loci, such as tubby (tub; QAW7.2), insulin-like growth factor I (Igfl
; QAW10.1), growth hormone (Gh; QAW11.1), and insulin I (Ins1; QAW19.1) are known to play key roles in the regulation of body growth and adult size, and are central in the physiological networks in which they participate.