Endocrine Abstracts

Introduction: Whereas the daily profiles of the main steroid hormones are well known, minor differences in the course of their levels related to defined and standardised food intake were studied rarely.

Methods: Eight women (mean age 29.48±2.99 years, mean BMI 21.3±1.3 kg/m²) in follicular phase of menstrual cycle were examined. The levels of C-peptide, glucose, LH, FSH, SHBG, cortisol, testosterone, dihydrotestosterone, progesterone, pregnenolone, oestrone and oestradiol were studied during a daily regimen (16 h) that included standardized food intake. The study protocol has been approved by Local Ethical Committee. A written informed consent was obtained from all participants.

Results: LH and FSH showed a monotonous decrease during the day with an implicated insignificant decrease after main meals. The course of androgen levels did not show much relation to food intake with the exception of dihydrotestosterone increase 2 h after lunch. SHBG evidently showed a small decrease after meals. C21 steroids showed a significant decrease 1 h after wakening up and then a monotonous decrease during the day. Cortisolemia continuously decreased during the day and an additional significant decrease of cortisol related to food intake was observed only 2 h after lunch. Estrogens did not show any striking trend of course during the day; oestradiol significantly decreased after lunch and dinner.

Conclusion: In our study the known nycthemeral rhythm of LH, FSH, cortisol, testosterone, progesterone and pregnenolone after food intake was confirmed but also significant changes after meals were observed in the levels of cortisol, estradiol and SHBG for the first time. The effect was seen only after the main meals (lunch and dinner). The effect of breakfast and snacks (small effect or long period from the meal and blood withdrawal) was probably hidden in the huge changes of the nycthemeral rhythm.

The study was supported by grants NT12340-5, NT11277-6, NT13890-4 IGAMZCR.

Disclosure: grants NT12340-5, NT11277-6, NT13890-4 IGAMZCR.