GHRP-2 and CJC-1295 without DAC (Mod GRF 1-29) are synthetic research peptides that are used together in experimental models to investigate the regulation of the growth hormone axis and somatotropic signaling pathways. GHRP-2 is a potent hexapeptide growth hormone secretagogue that activates the growth hormone secretagogue receptor (GHS-R1a) and triggers a Gq/PLC-dependent calcium signaling involved in GH release and hypothalamic-pituitary feedback regulation. CJC-1295 without DAC is a stabilized analog of growth hormone-releasing hormone (GHRH 1-29) that selectively activates the GHRH receptor, stimulating adenylate cyclase and cAMP-mediated signals in the somatotroph cells of the pituitary. Preclinical research uses the combined activation of GHS-R1a and GHRH receptors to study synergistic GH secretion, receptor pharmacology, and endocrine signaling dynamics in controlled laboratory environments.