Effect of aerobic exercise on lipaemia and its fatty acid profile after a meal of moderate fat content in eumenorrhoeic women

Exercise prior to eating has repeatedly been shown to reduce postprandial lipaemia. The aim of the present study was to investigate whether this effect was manifest in the presence of two factors that independently mitigate postprandial lipaemia: eumenorrhoea and moderate fat intake. Eight healthy eumenorrhoeic rowers consumed a meal of moderate fat content (35% total energy, 0·66g/kg body mass) 14h after having either rowed at 55% of maximal aerobic power (81% of maximal heart rate) for 80min or rested. Both trials were performed during the luteal phase. Blood samples were drawn before the meal and for 8h postprandially for the measurement of individual fatty acids in the triacylglycerol and NEFA fractions, as well as of glucose, insulin and oestradiol. Plasma oestradiol concentrations were not significantly different in the two trials. The postprandial lipaemic response, expressed as either plasma triacylglycerol concentration or area under the triacylglycerol–time curve, was 35% lower (P<0·05) after exercise. The postprandial glycaemic and insulinaemic responses were also lower, indicating increased insulin sensitivity, whereas the NEFA response was higher, suggesting a lower entrapment of dietary fatty acids in adipose tissue after exercise. Finally, exercise increased the proportion of unsaturated:saturated NEFA during the postprandial period. In conclusion, aerobic exercise performed 14h before a moderate-fat meal reduced postprandial lipaemia in women in the luteal phase. This effect shows the potential of exercise to mitigate even moderate lipaemic responses in eumenorrhoeic women.

Hypothalamic function in women during the first month post-partum

Plasma LRH-immunoreactive substance in puerperal women was very low on days 5 and 10 post-partum and significantly increased between days 10 and 20 post-partum, but remained at a similar level on day 30 post-partum, which was significantly lower than that in eumenorrhoeic women on day 8 or 9 of the normal cycle. Although LRH administration did not significantly increase serum FSH on day 11 post-partum, daily injections of LRH from days 5 through 10 post-partum caused a significantly increased secretion of FSH on day 11 post-partum, both basally and in response to LRH. No significant difference was observed in serum oestradiol and Prl levels on day 11 post-partum between the two groups of women with and without LRH pre-treatment. It is concluded that the amount of hypothalamic LRH secretion may be small during the first month post-partum, and low basal FSH and unresponsiveness of the pituitary to LRH observed in the early puerperium may result from hypothalamic hypofunction.

INFLUENCE OF LH/FSH RELEASING HORMONE (LRH) ON THE BASAL SECRETION OF GONADOTROPHINS IN RELATION TO PLASMA LEVELS OF OESTRADIOL, PROGESTERONE AND PROLACTIN DURING THE POST-PARTUM PERIOD IN LACTATING AND IN NON-LACTATING WOMEN

ABSTRACT The pituitary responsiveness to LH/FSH releasing hormone (LRH) was studied in the puerperium in lactating and in non-lactating women. The response of both groups of patients to 25 μg LRH iv was tested 8–10 days, 15–17 days, and 29–32 days after a normal delivery at full term. The basal levels of FSH were low during the first 10 days after delivery. A rise was then observed, and about 4 weeks after delivery levels above or in the upper normal range of a normal follicular phase were recorded. The levels were significantly higher in the lactating group. When compared with the normal follicular phase, the relative increase in FSH basal levels was higher than the increase in LH basal levels in both groups of patients. The period of non-responsiveness of the pituitary to LRH was found to be of equal length in the two groups. In both groups the FSH response returned more rapidly than the LH response. About 2 weeks after delivery a reverse pattern of gonadotrophin response to LRH was seen with a FSH response that was greater than the LH response compared with what is generally observed in the various phases of the menstrual cycle in eumenorrhoeic women. This pattern was more pronounced in the lactating group about 4 weeks after delivery. Oestradiol levels were low and roughly equal on the three test occasions in each group, but in the non-lactating group there was a tendency to higher concentrations. Prolactin levels were highest about one week after delivery and then showed a tendency to decrease, and this was more pronounced in the non-lactating group. Progesterone levels were invariably low in both groups.