The ADRB3 gene, or adrenergic receptor beta 3, plays a significant role in various physiological processes, particularly in the context of metabolism and energy regulation. Below are additional details that expand upon the basic information provided in the NCBI and UniProt summaries:

### 1. Associated Genes:
ADRB3 gene has been associated with several other genes, especially those involved in metabolism, obesity, and the adrenergic signaling pathway. Some of these include:
- **LEPR (Leptin Receptor)**: Involved in body weight regulation and energy homeostasis.
- **PPARG (Peroxisome Proliferator-Activated Receptor Gamma)**: Regulates fatty acid storage and glucose metabolism.
- **ADRB1 (Adrenergic Receptor Beta 1)** and **ADRB2 (Adrenergic Receptor Beta 2)**: Other beta-adrenoceptors that are part of the same signaling family.
- **CAMP (Cyclic Adenosine Monophosphate)**: The primary second messenger involved in the signaling pathway mediated by adrenergic receptors.

### 2. Aging and Age-Related Diseases:
Research has shown that variations in ADRB3 may influence the risk of developing obesity and metabolic syndrome, conditions commonly associated with aging. Specifically:
- Polymorphisms in the ADRB3 gene (such as the Trp64Arg variant) have been linked to obesity, suggesting that age-related weight gain may be exacerbated by specific genetic predispositions.
- The role of ADRB3 in regulating lipolysis may also relate to age-related changes in body composition, as aging is often accompanied by increased fat mass and decreased lean muscle mass.

### 3. Drug Interactions:
ADRB3 interacts with several drug classes and specific drugs primarily related to obesity and metabolic disorders:
- **Beta-adrenergic Agonists**: These include drugs like **Mirabegron**, which is primarily used for overactive bladder but has also been examined for its potential effects on metabolism.
- **Weight Loss Medications**: Any sympathomimetic agents that may stimulate adrenergic receptors (e.g., certain appetite suppressants).
- **Beta-blockers**, primarily those that are non-selective, can antagonize the action of ADRB3.

### 4. Pathways and Biological Processes:
ADRB3 is involved in numerous biological pathways and processes:
- **Catecholamine Signaling Pathway**: Mediates effects of catecholamines such as epinephrine and norepinephrine.
- **Adenylate Cyclase Activation**: Leads to increased production of cAMP, serving as a second messenger in various signaling cascades.
- **Lipolysis**: Promotes the breakdown of fats into fatty acids and glycerol, playing a crucial role in energy homeostasis.
- **Thermogenesis**: Particularly important in brown adipose tissue where it contributes to heat production.
- **Regulation of Glucose Metabolism**: ADRB3 plays a role in insulin sensitivity and glucose uptake, linking it also to metabolic syndrome and potential diabetes risk.

In summary, the ADRB3 gene is a critical player in metabolic pathways, particularly in relation to energy expenditure and fat metabolism, with implications in obesity, aging, and drug pharmacology. Further studies continue to explore its role in various diseases and potential therapeutic targets.