Yes, a hormonal imbalance can cause panic disorder. The neurobiology of the development of panic attacks stems from the release of the hormone adrenaline from the adrenal glands to the bloodstream. During the fight or flight response, the fear center of the brain, the amygdala, is activated and this in turn triggers both the hypothalamic-pituitary-adrenal axis (HPA axis) and the sympathetic nervous system.
The sympathetic nervous system then triggers the adrenal medulla (the middle part of the adrenal glands) to release adrenaline into the bloodstream. The adrenaline then courses through your body and gives rise to the symptoms of a panic attack, such as racing heart, pounding chest, and sweating.
The HPA axis also releases hormones when the amygdala triggers the hypothalamus to release the hormone corticotropin releasing factor (CRF). CRF then travels to the pituitary, which releases adrenocorticotropic hormone (ACTH) into the bloodstream. The ACTH then travels to the adrenal glands, and stimulates the adrenal cortex (the outer part of the adrenal glands) to release more stress hormones such as cortisol. Cortisol also contributes to the development of panic attacks, as cortisol increases blood glucose which fuels the panic attack response. Cortisol also travels to the brain and further enhances the panic attack response by further enhancing the overactive fear circuits centered in the amygdala.
So as you see, the hormone imbalance of excess adrenaline and excess cortisol from the fight or flight response can cause panic disorder.