In vitro effects of methionine-enkephalin, somatostatin and insulin on cultured gonadal cells of the snailHelix aspersa

Abstract

Isolated snail gonadal cells were cultured in the presence of synthetic neuropeptides in order to determine the subsequent effect of these substances on gonadal synthetic activities. Gonadal cells were incubated for 24 h in concentrations of methionine-enkephalin, somatostatin and insulin ranging from 10(-4) M to 10(-9) M, in medium 199 supplemented with 6% Ultroser G. Synthesis of DNA and protein by the cultured cells were simultaneously estimated by measuring incorporation of 3H thymidine and 35S methionine. The rate of labelled precursor incorporation was measured using the liquid scintillation technique. All substances tested exerted a dose-dependent effect. The synthetic activity of the cultured cells was highest when the concentration of the peptides added to the medium approximated the physiological levels. Methionine-enkephalin, somatostatin and insulin at 2 x 10(-8) M significantly increased 3H thymidine incorporation, by 62%, 69% and 69% respectively, and protein synthesis by 42%, 57% and 57%, respectively. In the case of juvenile gonadal cultured cells, a similar increase in 3H and 35S incorporation was registered for a 10(-7) M peptide concentration. Both lower and higher peptide concentrations inhibited 3H thymidine and 35S methionine incorporation. Pharmacological studies suggest the existence of methionine-enkephalin and somatostatin-like receptors on snail gonadal cells. These results indicate that our gonadal cell culture model provides a useful tool for the study of the neuroendocrinological control of the activity of snail gonadal cells.

Identification and Characterization of Neuropeptides by Transcriptome and Proteome Analyses in a Bivalve Mollusc Patinopecten yessoensis

“…Molluscan insulin-related peptide is a growth stimulating hormone related peptide involved in glucose metabolism and growth ( Ebberink et al, 1989 ). It may also participate in the regulation of germinal cell proliferation and maturation ( Monnier and Bride, 1995 ). Molluscan insulin-related peptides have been determined in the snail L. stagnalis ( Smit et al, 1988 , 1996 ; Li et al, 1992b ), limpet L. gigantea ( Veenstra, 2010 ), and slugs A. californica ( Floyd et al, 1999 ) and D. reticulatum ( Ahn et al, 2017 ).…”

In silico prediction of neuropeptides from the neural ganglia of Pacific abalone Haliotis discus hannai (Mollusca: Gastropoda)

“…These neuropeptides are involved in the growth and glucose metabolism (Ebberink et al 1989). They also play a role in mediating germinal cell proliferation and maturation (Monnier & Bride 1995). Three insulin-like precursors (Insulin-like 2A, 2B, and MIP-related peptide) were identified in H. discus hannai.…”

Characterization of Insulin-like Peptide (ILP) and Its Potential Role in Ovarian Development of the Cuttlefish Sepiella japonica

“…The involvement of ILPs in the regulation of carbohydrate metabolism has also been reported in invertebrates, such as Lymnaea stagnalis [ 41 ] and Aplysia californica [ 3 ]. In this study, the relatively greater abundance of Sj ILP mRNA transcript in the pancreas suggests the paracrine function of insulin-like peptides during digestion ( Figure 7 A) [ 16 ]. In mollusks, neurosecretory cells in the cerebral ganglia are the main source of ILPs [ 42 , 43 , 44 ].…”

“…In Planorbarius corneus [ 14 ] and Lymnaea stagnalis [ 6 ], ILPs have been detected in the brain and are involved in the hormonal control of reproduction [ 15 ]. In isolated gonadal cells of Helix aspersa , Monnier and Bride [ 16 ] showed that vertebrate insulin stimulated protein synthesis, suggesting that ILPs may be involved in the regulation of germinal cell proliferation and maturation. In the Pacific oyster Crassostrea gigas , Cg- ILP is mainly expressed in the gonadal area, suggesting involvement in the control of sexual reproduction [ 5 ].…”