In memoriam Josephine Arendt

Josephine Arendt Ph D,FRCPath, FRSM, Dr med h c

Emeritus Professor of Endocrinology at the University of Surrey

We are saddened to hear that the grand pioneer of melatonin research, Josephine Arendt, unexpectedly died at home in Guernsey on Monday 4 September 2023.

Jo Arendt began her scientific life as a biochemist, with a PhD on 5-hydroxyindole metabolism under the legendary Merton Sandler at the University of London. So she was already knowledgeable about serotonin pathways in the brain when she achieved what was at the time considered impossible – creating a radioimmunoassay for a small molecule.  This small molecule synthesised from serotonin became her life’s work: melatonin. She studied melatonin in the pineal gland, retina, and body fluids;  in different species from tortoise to quail to sheep to humans. She was curious about its role in seasonal behaviour, reproduction, and sleep. Standardised assays in plasma, saliva, and urine became a world-wide applied tool (developed in her lab and firm Stockgrand) for her many collaborators. 

Jo was a pioneer in so many aspects of melatonin’s role(s):  the first study in jet lag; dissecting out rhythm changes in patients with depression or induced by antidepressant drugs; how melatonin stimulated sleepiness and whether it affected nocturnal sleep. Its role as zeitgeber could be most clearly documented in the long-term controlled trials to phase shift and stabilise sleep-wake cycles in the blind. A potential application was to improve shift workers’ tolerance of the night shift. 

She always worked with animals as a fundamental method for understanding clinical applications. With melatonin, she was looking at the dark phase. But soon she moved to daytime. Understanding the mechanisms of light via the eye on circadian rhythms naturally involved melatonin as marker.  The unusual social and photoperiodic conditions of Antarctica inspired her for over three decades to investigate what extreme light conditions do to human behaviour and physiology. When seasonal affective disorder was (re)discovered, she was involved in the melatonin-related theories and assays for many psychiatric researchers, including our lab in Basel. The effects of light therapy could be closely followed, the effects of wavelength specified more carefully. She was a founding member of the Society for Light Treatment and Biological Rhythms, and all of us in the field profited from her research. 

Jo was my oldest and closest collaborator,  we celebrated so much together, in science and in life. She was generous, funny, widely knowledgeable, supportive, inspiring, and adventurous (she went to Antarctica on an icebreaker).  Already deeply missed.

Anna Wirz-Justice