What chemical reactions take place before, during and after panic attack, fear and anxiety in males?

Hundreds! There are lots of chemical reactions going on in our body at any time. With fear (whether to a known cause or due to panic attacks which can happen for unclear reasons or with no definite threat) one of the main ones is the adrenaline surge (fight or flight response) which causes a multitude of reactions itself. See https://en.wikipedia.org/wiki/Fight-or-flight_response.
Neural and chemical. The first moments of a panic attack trigger a rapid reaction in the Autonomic Nervous System (ANS) -- high levels of sympathetic arousal in ANS. Heart rate and breathing are affected. Then in a minute or so the endocrine system kicks in - the adrenal glands secrete adrenaline and other corticosteriods. Continued panic triggers hyperventilation, producing other chemical changes in body. Both M/F.
Anxiety attacks. generate adrenaline and some stress hormones that do several things--raise heart and respiration rates, push the brain into the beta range (fast thinking), refine your senses (sensitivity), turn off your digestion, cause your fat cells to dump glucose into the blood, and decrease blood circulation to extremities. This occurs in both genders.
Anxiety biochemistry. Dr. Candace Pert's, 'Molecules of Emotion' is a great book explaining the process of how the fight or flight response is the production of neuropeptides, and that we interpret the physical sensations according to how we interpret the event.So being able to shift your perspective to look at things from a mastery perspective helps greatly.The biochemistry is adaptive-we just need to know what to do.
Genera Adaptation. Syndrome (GAD) takes place. At first your excitatory neurotransmitters like adrenaline surge. As the panic attack runs its course (and they are self-limiting) the inhibitory neurotransmitters such as serotonin serge and there can be a feeling of weakness for a short while. These levels can be tested at a lab. One is www.neurorelief.com Urine is the sample used. Peace and good health.