Identify the location and primary function of the following: $(1)$ Prolactin,$(2)$ $ADH$,$(3)$ Pineal gland.

(N/A) $(1)$ Prolactin: Located in the anterior pituitary gland. Its primary function is to regulate the growth of mammary glands and milk production in mammals.
$(2)$ $ADH$ (Antidiuretic Hormone/Vasopressin): Synthesized by the hypothalamus and stored/released by the posterior pituitary gland. Its primary function is to stimulate the reabsorption of water and electrolytes by the distal tubules of the kidney,thereby reducing water loss through urine.
$(3)$ Pineal gland: Located on the dorsal side of the forebrain. Its primary function is to secrete melatonin,which plays a crucial role in regulating the $24-$hour (diurnal) rhythm of our body,such as the sleep-wake cycle and body temperature.