Influences of Norepinephrine, and Adrenergic Agonists and Antagonists on Gonadotropin Secretion from Dispersed Pituitary Cells of Goldfish, <i>Carassius auratu</i><i>s</i>

Abstract

Static incubations of dispersed goldfish pituitary cells with 1–100 nM norepinephrine (NE) stimulated gonadotropin (GTH) release. Additions of the α-agonist phenylephrine, and the αi-agonist 6-fluoronorepinephrine, but not the α₂-agonist clonidine, nor the β-agonist isoproterenol, also enhanced GTH secretion. The GTH responses to 1 nM NE was significantly inhibited by coincubations with 1 µM of the α-antagonist phentolamine, the α₁-antagonists prazosine and benoxathian, but not the α₂-antagonist yohimbine nor the β-antagonist propranolol. The GTH responses to NE and phenylephrine were also additive to salmon GTH-releasing hormone (sGnRH)-induced GTH release. These results suggests that NE directly stimulates GTH secretion independent of sGnRH receptors via α₁-like adrenergic receptors.

Association between antidepressant medication use and epithelial ovarian cancer risk: a systematic review and meta‐analysis of observational studies

“…Human studies have also shown that stimulation of dopaminergic receptors is involved in the release of luteinizing hormone, follicle-stimulating hormone, and prolactin [11,[57][58][59]. Increases in endogenous norepinephrine have been shown to induce gonadotropin secretion as well [54,60]. Fluoxetine, a type of SSRI, was demonstrated to induce apoptosis of ovarian carcinoma OVCAR-3 cells [61].…”

Signal transduction mechanisms mediating secretion in goldfish gonadotropes and somatotropes

“…NE stimulation of GTH-II release is mediated through alpha-1-like adrenergic receptors (Chang et al 1991b). Although the GTH-II response to NE has been reported to be additive to responses elicited by GnRH (Chang et al 1991b), little is known regarding the intracellular signaling mechanisms of NE.…”

“…Although the GTH-II response to NE has been reported to be additive to responses elicited by GnRH (Chang et al 1991b), little is known regarding the intracellular signaling mechanisms of NE.…”

“…As a result of these and other central mechanisms (reviewed in Trudeau and Peter 1995), the peri-ovulatory increases in serum GTH-II and GH levels are manifested. It is also possible the NE, through alpha-1 action, contributes to the serum GTH-II increase during early gonadal recrudescence (Chang and Peter 1984;Chang et al 1991b), while exerting a negative modulatory influence on the GH release response through alpha-2 mediated actions on somatotropes.…”

Estradiol Stimulates Growth Hormone Production in Female Goldfish

“…Conversely, GH release is inhibited by glutamate (Trudeau et al, 1996), norepinephrine (Chang et al, 1991), serotonin (Somoza and Peter, 1991), and somatostatin (SRIF; Marchant et al, 1987;Wong et al, 1993). The interaction of these multiple stimulatory and inhibitory neurohormones is the likely driving force generating seasonal rhythms in serum GH levels and somatic growth (see Peter and Marchant, 1995, for review).…”