Nyctohemeral pattern of serum LH, FSH and PRL in patients with myotonic dystrophy.

The nyctohemeral pattern of serum luteinizing (LH), follicle-stimulating hormone (FSH) and prolactin (PRL) in eight patients with myotonic dystrophy (MD) was studied. Gonadotropin patterns were classified as adult, pubertal or infantile. Six patients showed an adult pattern, whereas two had a pubertal or infantile pattern. A normal pattern of PRL secretion was found in seven patients and a blunted sleep-related hormonal increase was observed in one. Impaired hypothalamic control of pituitary secretion in MD is proposed as the cause for these findings.