While prolactin is best known for its role in mammals in promoting
milk production from mammary glands, vertebrates developed prolactin
long before mammals evolved. Prolactin is known to have more than 300
functions in vertebrates, more than the roles of all other pituitary
hormones combined. One of its major roles in fish is the control of
osmotic balance (Manzon, 2002).
ORGASM AND THE REFRACTORY PERIOD
Hypersecretion of prolactin results in the loss of menstrual cycles and reduced sperm production (Tillmann, 2002). Some drugs, such as neuroleptics and antidepressants, can increase prolactin levels, decrease sexual drive, cause delayed orgasm in men and women, or anorgasmia in women (Tillmann, 2002). Hyperprolactinemia is associated with decreased libido and sexual disfunction. Some of the effects of chronic antidepressant and antipsychotic medications are through changes in prolactin release (Exton, 2001). Female sexual dysfunction occurs in almost 90% of women who suffer from hyperprolactinemia. Hyperprolactinemia is the most common endocrine disorder of the hypothalamic-pituitary axis (Kadioglu, 2005).
Cortisol, LH, FSH, GH, E, testosterone, and ß-endorphin
are not affected by orgasm after masturbation. Levels of NE increase during
orgasm briefly and prolactin levels remain elevated for a half hour afterwards