[The effect of a short-term reducing regimen on hormonal secretion in obese patients]

A twelve-day reducing regime involving exercise and a reducing diet (2.5 MJ/day), led in 23 obese women to an average loss of body weight of 4.52 +/- 0.35 kg. The loss of adipose tissue during the reducing regime was greater than the total loss of body weight, obviously due to proliferation of lean body mass as a result of exercise. Concurrently a significant decline of the mean morning concentration of thyroxine, triiodothyronine, C-peptide and STH in serum was recorded, while the concentration of TSH, cortisol, prolactin, LH and FSH increased insignificantly and the concentration of insulin and testosterone declined insignificantly. Exercise thus did not prevent a decline of triiodothyronine induced by the low energy diet. The exercise in the morning did not cause a stress conditioned increase of the secretion of cortisol, prolactin and STH at the onset and at the end of the reducing regime. From the metabolic aspect the favourable absence of the stimulating action of exercise on cortisol secretion is due to the character of motor activity (40-50% VO2max). The absence of a stress conditioned rise of prolactin during exercise prevents the inhibiting action of prolactin on gonadal functions. The reducing regime has also a favourable effect on insulin secretion, as on the 12th day of the reducing regime there was a significant decline of the serum level of immunoreactive insulin in the course of exercise.