This is a randomized, double-blind, placebo-controlled Phase I clinical trial evaluating the safety, tolerability, pharmacokinetics, immunogenicity, and preliminary pharmacodynamic characteristics of GR2301 injection in healthy adult subjects in China.The GR2301 injection dosage will be gradually increased. All healthy subjects will receive a single subcutaneous injection. Following administration, subjects will be followed for at least 16 weeks ± 7 days.

Main Inclusion Criteria:

1. BMI 19.0-28.0 kg/m², with male subjects weighing ≥50.0 kg and female subjects weighing ≥45.0 kg；
2. Understand and comply with the requirements of the clinical protocol, voluntarily participate in the clinical trial, and sign the informed consent form.

Main Exclusion Criteria:

1. A history of past or current conditions involving the nervous system, cardiovascular system, urinary system, digestive system, respiratory system, endocrine system, metabolic system, or other clearly documented medical conditions, which the investigator deems may pose a risk to the subject's safety or interfere with the conduct, progress, or completion of the trial.
2. History of drug use or substance abuse, or positive urine drug screening prior to enrollment.
3. Pregnant and breastfeeding women.