Fight-or-flight reactions cause activation of

Adrenaline and noradrenaline are rapidly secreted by adrenal medulla in response to stress of any kind and during emergency situations and are called emergency hormones or hormones of Fight or Flight. These hormones increase alertness, pupilary dilation, piloerection (raising of hairs), sweating etc. Both the hormones increase the heartbeat, the strength of heart contraction and the rate of respiration. 

The glucose homeostasis in blood is maintained jointly by the two hormones – insulin and glucagon, which are secreted by pancreas. 

A fall in GFR activates RAAS (Renin Angiotensin Aldosterone System). 

Parathyroid hormone is secreted by parathyroid gland in response to hypocalcemia.