The crustacean stomatogastric nervous system (STNS) is a well-known model for investigating neuropeptidergic control of rhythmic behavior. Among the peptides known to modulate the STNS are the C-type allatostatins (AST-Cs). In the lobster, Homarus americanus, three AST-Cs are known. Two of these, pQIRYHQCYFNPISCF (AST-C I) and GNGDGRLYWRCYFNAVSCF (AST-C III), have non-amidated C-termini, while the third, SYWKQCAFNAVSCFamide (AST-C II), is C-terminally amidated. Here, antibodies were generated against one of the non-amidated peptides (AST-C I) and against the amidated isoform (AST-C II). Specificity tests show that the AST-C I antibody cross-reacts with both AST-C I and AST-C III, but not AST-C II; the AST-C II antibody does not cross-react with either non-amidated peptide. Wholemount immunohistochemistry shows that both subclasses (non-amidated and amidated) of AST-C are distributed throughout the lobster STNS. Specifically, the antibody that cross-reacts with the two non-amidated peptides labels neuropil in the CoGs and the stomatogastric ganglion (STG), axons in the superior esophageal (son) and stomatogastric (stn) nerves, and ~ 14 somata in each commissural ganglion (CoG). The AST-C II-specific antibody labels neuropil in the CoGs, STG and at the junction of the sons and stn, axons in the sons and stn, ~ 42 somata in each CoG, and two somata in the STG. Double immunolabeling shows that, except for one soma in each CoG, the non-amidated and amidated peptides are present in distinct sets of neuronal profiles. The differential distributions of the two AST-C subclasses suggest that the two peptide groups are likely to serve different modulatory roles in the lobster STNS.

Serum concentration of follicle-stimulating hormone (FSH) in the juvenile female rat increases independently from that of luteinizing hormone (LH). The objective of this study was to determine whether this increase in serum FSH is accompanied by a proliferation of FSH-cells greater than the proliferation of LH-cells. Thus, we measured circulating FSH and LH in female rats on days 3, 10, 13, 17, and 20, calculated the percentages of adenohypophyseal cells that contained FSH or LH on days 3, 10, and 20, and determined whether cells containing only FSH existed on day 10. Serum FSH concentrations on days 10 and 13 were significantly greater than those on days 3, 17, or 20. No differences existed in serum LH concentrations. Cells containing FSH or LH were distributed throughout the entire adenohypophyses of 3, 10, and 20-day-old females. Clusters of these cells were observed in the ventral regions of adenohypophyses of 3-day-old females. The percentages of adenohypophyseal cells containing FSH increased significantly from approximately 9% in 3-day-old rats to approximately 17% in 10-day-old rats and then decreased to approximately 14% in 20-day-old animals. At all ages the percentages of adenohypophyseal cells containing FSH were similar to the percentages of cells containing LH. At 10 days of age, all cells containing FSH also contained LH and all cells containing LH also contained FSH. These data suggest that the increase in serum FSH in the juvenile female rat is associated with an increase in the percentage of adenohypophyseal cells containing FSH and that at this time all cells containing FSH also contain LH.