The 24-hour rhythm of oxytocin and beta-endorphin secretion in human pregnancy.

OBJECTIVE: Animal work suggests that maternal oxytocin secretion is influenced by the secretion of endogenous opioids in pregnancy. Spontaneous labour and pre-labour uterine activity follow a 24-hour rhythm the origin of which has not been explained but may be related to diurnal changes in oxytocin secretion. This study was performed to document the changes over a 24-hour period in maternal oxytocin and beta-endorphin secretion. DESIGN: A 4-hourly blood profile was undertaken for a 24-hour period. PATIENTS: Sixteen women with singleton pregnancies of more than 36 weeks gestation and 10 women with pregnancies in the mid trimester were studied. MEASUREMENTS: Blood was sampled 4-hourly for 24 hours beginning at 1200 h. Oxytocin was measured in all patients and beta-endorphin-like immunoreactivity was measured in 15 patients. RESULTS: A simple index was defined for comparing night-time levels to daytime levels for both oxytocin and beta-endorphin. In all cases more than 36 weeks gestation the index was positive for oxytocin (night-time levels were higher) and in all cases the index was negative for beta-endorphin (night-time levels were lower). In the mid trimester women all values of the index for oxytocin were positive but in the beta-endorphin group equal numbers demonstrated a positive or a negative index. CONCLUSIONS: Reciprocal 24-hour rhythms were demonstrated between oxytocin and beta-endorphin; however, it is not clear whether this relationship is causal.

Laparoscopic findings in women with chronic pelvic pain.

OBJECTIVE: This study was undertaken to assess the spectrum of pelvic pathology observed at laparoscopy in women with chronic pelvic pain, and to compare women with an identifiable cause of pain to those with no visible pelvic pathology, with regard to symptomatology and demography. DESIGN: Retrospective case control study reviewing laparoscopy reports and patient records. SETTING: Department of Obstetrics and Gynaecology, Groote Schuur Hospital. PATIENTS: One hundred and thirty-six consecutive women undergoing laparoscopic assessment for undiagnosed pelvic pain of at least 6 months' duration, between 1989 and 1991. MAIN OUTCOME MEASURES: The presence of endometriosis, pelvic adhesions, other pelvic pathology and 'negative' laparoscopic findings was assessed. The association between pelvic pathology and specific symptomatology, fertility, contraceptive use, past pelvic surgery, ethnic group and smoking is examined. RESULTS: No cause of pain was identified at laparoscopy in 30% of these patients, while endometriosis was found in 16% of women and pelvic adhesions in 40%. The 41 women with no identifiable laparoscopic abnormality did not differ significantly from the 95 with pelvic abnormalities in respect of age, parity, duration of pain, frequency of dysmenorrhoea and dyspareunia or the presence of gastro-intestinal or urinary symptoms. However, injectable hormonal contraception use was more common in the group with negative laparoscopic findings and smoking was more common among the women with pelvic pathology. CONCLUSION: Chronic pelvic pain with a laparoscopically normal pelvis is a common problem in Cape Town, occurring with a frequency similar to that reported from various overseas centres. Women with this problem are not readily identified by demographic profile or symptom complex.

Changes in activity and intra-acinar distribution of glucose-6-phosphate dehydrogenase and malic enzyme during pregnancy in rat liver.

Using techniques of microdissection and microassay as well as qualitative histochemistry the activity and intra-acinar distribution of G6PDH and ME were studied on selected days of pregnancy in the rat. Both enzymes show distinct fluctuations during the course of pregnancy in keeping with changes in hepatic lipogenesis. Marked increases in activity are seen as early as the 4th day, while highest values are attained on day 20, with a predominant perivenous induction. On day 22, just before parturition a sharp decrease of both enzyme activities with a flattening of the periportal/perivenous gradient was detected. G6PDH shows proportionally considerably larger increases and more distinct changes in zonation. The perivenous fluctuations in G6PDH activity of late gestation are supposed to be caused primarily by insulin. Although estrogen is known to induce both enzymes, the temporal changes in enzyme activity in pregnancy cannot be related to the action of estrogen alone. The changes in enzyme activity, however, correspond well to those of progesterone, and although no direct action of progesterone on these enzymes has yet been proposed, further work on its effects on enzyme activity and distribution is indicated.