cervical incompetence previous cesarean section premature labor. P regnant with cervical incompetence with labor. 32 . 3 fetal distress radical operation repair.
Endocrinol. Japan . 1985, 32 (6), 875-880
Effects of Pregnancy and Labor on Oxytocin Levels in Human Plasma and Cerebrospinal Fluid SATORU TAKEDA, YosHINORI KUWABAR A AND MASAHIKO MIZUNO
Department of Obstetrics and Gynecology, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo , Bunkyo-ku, Tokyo llJ.
Abstract In order to investigate the significance of oxytocin in pregnancy and labor, oxytocin concentrations in plasma and cerebrospinal fluid (CSF) were determined using the specific radioimmunoassay. Plasma and CSF samples were obtained from 23 pregnant women (11 pre labor, 12 in labor), 15 nonpregnant women and 4 men at spinal puncture for anesthesia. In males and nongravidas, CSF levels of oxytocin were significantly higher than plasma levels. Plasma levels in pregnant patients pre or in tabor were significantly higher than those in nongravidas. No significant difference between CSF levels in prelabor gravidas (mean± SE, 9.7±1.5 µu / ml) and nongravidas (1 0.1±1.2 µu / ml) was found. However, CSF levels in gravidas in labor (18.6± 2.3 µu /ml) were significantly higher than the levels in prelabor gravidas. These results strongly suggest that oxytocin levels in human plasma and CSF are controlled by different mechanisms and that the increased oxytocin could have some specific central actions.
It is well known that oxytocin is synthesized in cell bodies located mainly in the paraventricular nucleus and the su praoptic nucleus of the hypothalamus and is transported along the axons of these cells to the posterior pituitary by the carrier protein neurophysin , and released into the bioodstream in response to various stimuli. It is also known that extensive oxytocic neurosecretory fibers are located in the extrahypothalamic brains as well as in the posterior pituitary. However. the physio logical roles of oxytocic neurons in the extra hypothalamic brains remain obscure.
Recei ved Jul y 30, 1985
R ecently the central actions of neurohypophysial peptides have been made clear by administerin g these peptides into the cerebroventricles and the several parts of the brain . It is reported that in rats oxytocin is involved in memory process~s and has amnesic effects that are generally opposite to the effects of vasopressin. In order to investigate the central action of oxytocin, it is important to know the oxytocin concentrations in plasma and cerebrospinal fluid (CSF) . The oxytocin levels in the CSF of some mammalian species have been reported, but the human levels are still unclear. In this study we have determined the oxytocin concentrations of plasma and
876
Endocrinol. Japon. December 1985
TAKEDA et al.
CSF in men, nonpregnant women and pregnant women using specific RIA, following extraction procedures with Florisil.
Materials and Methods Materials and Subjects Forty-two patients without endocrine or brain diseases were chosen. (Table 1) Fifteen nonpregnant women (aged 30-52) suffered from gynecological diseases such as uterine myoma, ovarian tumor and Bartholin's cyst. Twenty-three pregnant women (aged 28-39) between 7 weeks and 43 weeks of gestation had D & C, ovarian cystectomy, cervical suture or Cesarean section. The operations were performed in 11 patients before labor and 12 patients in labor. Three preterm cases in labor recei ved intravenous p2 adrenergic stimulant (ritodrine) before and after operation. Four male patients (aged 17-40) had minor operations for hemorrhoids, tibia fracture or inguinal hernia. All patients received atropine sulphate, 0.5 mg i.m., one hour before the operation as anesthesia premedication. All operations were performed between 10: 00 h and 15: 00 h. The blood and CSF samples were taken at spinal puncture for anesthesia. The patients gave consent for the
CASES
Male
Nonpregnant
Pregnant wit hout labor
P regn ant wit h labor
MEAN AGE
30. 3
40 . 2
DIAGNOSIS
Methods The assay sample (1-2 ml) was mixed with 200 mg of Florisil (100-200 mesh) using a vortex mixer for 5 min and centrifuged for 5 min at 3000 rpm. The supernatant was discarded. The residual part of the Florisil was washed with 1 ml of IN HCI, and again with 1 ml of distilled water. Peptides were eluted by vigorous mixing with 2.5 ml of 80% aqueous acetone. The supernatant acetone phase was transferred to a silicone coated glass tube. Three ml of ether was added. After mixing, the upper organic phase was discarded. The lower aqueous phase was blown to dryness
OPERATION
NUMBER
bone fracture
repair
1
inguinal hernia
re pa ir
1
uter ine myoma
abdominal to'.al hysterectomy
8
benign ovarian turner
cystectomy
5
Ba rtholin's cyst
cystectomy
2
termination of the pregnancy
D&C
1
benign ovarian tumor
cystectomy
2
cervic al incompetence
Shi rodkars operation
2
previous cesarean section
cesarean se ct ion
6
fetal distress
emergency cesarean section
AI
bits b bovin sensit cent 1 of 1 : pressi 0.07 charc was ( coeffi• 15.4
