Effects of Sex Steroid Hormones on the Expression of Somatostatin Receptors sst1 and sst5 in Goldfish Pituitary and Forebrain

Abstract

In the present paper the effects of estradiol and testosterone on the expression of the types 1 and 5 somatostatin receptors (sst1 and sst5) in the goldfish forebrain and pituitary were investigated. Estradiol increased the sst1 expression in both the forebrain and pituitary in a dose- and time-dependent manner. In addition, estradiol also increased the pituitary expression of sst5. On the other hand, testosterone had no effects on the expression of these receptor subtypes. Mature female goldfish were found to have higher sst1 and sst5 expression in the pituitary, as well as a higher expression of sst1 in the forebrain compared to sexually regressed animals. As estradiol treatment increases serum growth hormone levels in goldfish, these data suggest that sst1 and sst5 receptors are likely not directly involved in this aspect of growth hormone release.

Periprandial changes in growth hormone release in goldfish: role of somatostatin, ghrelin, and gastrin-releasing peptide

“…The results, shown in Fig. 4, confirm that intraperitoneal administration of 50 ng/g body wt of ghrelin (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) has no significant effect on PSS-I expression levels (Fig. 4A), whereas it inhibits the expression of PSS-II (Fig.…”

“…It was recently shown that estradiol treatment reduces the in vitro GH responsiveness to SRIF-14 and simultaneously reduces the expression levels of sst2 in goldfish pituitary (12). However, estradiol treatment increases the expression levels of sst5 (9). Thus it seems that sst5 may be specialized in the transduction of gSRIF-28 actions in the pituitary.…”

“…Goldfish ghrelin (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) with an octanoyl modification in the Ser 3 residue was synthesized in the laboratory of Dr. Jean E. Rivier (Clayton Foundation Laboratories for Peptide Biology, The Salk Institute of Biological Sciences, San Diego, CA). Stock solutions were made in fish physiological saline (0.65% NaCl) or Milli-Q water, aliquoted, and stored at Ϫ20°C.…”

Estrogens Modulate Somatostatin Receptors Expression and Synergize With the Somatostatin Analog Pasireotide in Prostate Cells

“…Therefore, SSTRs represent a target for PC therapies, although the mechanism of their action as well as their cross talk with steroid receptors is still unclear. Estrogens up-regulate SSTR expression in BC cells as well as in goldfish pituitary and cerebral tissues (Djordjijevic et al, 1998; Kimura et al, 2001; Canosa et al, 2003). However, the effect of the combined treatment of SST analogs and estradiol on proliferation, EMT and migration of normal and PC cells has not been investigated so far.…”

Insulin and growth hormone stimulate somatostatin receptor (SSTR) expression by inducing transcription of SSTR mRNAs and by upregulating cell surface SSTRs

“…Previous studies in goldfish, rainbow trout, and mammals reported the effects of other hormones, including 17␤-estradiol, glucocorticoids, SS, and GH-releasing hormone (GHRH) on SSTR expression (4,16,19,21,22,31). For example, in rainbow trout, in vivo INS treatment reduced SSTR1B expression in the optic tectum, increased SSTR2 expression in the pancreas, and increased SSTR1B and SSTR2 expression in the liver (31).…”