[:en]Circadian Rhythm of Serum Testosterone and Its Relation to Sleep[:]
[:en] By Robert Gorter, MD, PhD, Robert Gorter, MD, PhD, is emeritus professor of the University of California San Francisco (UCSF) Dr. Robert Gorter: “Nocturnal penile tumescence (abbreviated as NPT), also known colloquially as morning wood, morning erections, or morning glory, is a spontaneous erection of the penis during sleep or when waking up. All