The cannulation of the caudal caval vein through the femoral vein in the pig for endocrine research.
The present study was designed to examine the usefulness of cannulation of the caudal caval vein through the femoral vein for the measurement of hormone concentrations in the reproductive tract in the pig. The experiment was performed on sexually pubertal gilts (Polish Large White x Polish Landrace) of a similar age (7-8 months) and body mass (100-110 kg) after two controlled subsequent estrous cycles. Six gilts in the luteal phase (10th day) of the estrous cycle were used in this experiment. The animals were subjected to a surgical procedure which included:--premedication (Combelen, i.m. 1 ml/10 kg of body mass) and than after 20-30 min general anaesthesia (Vetbutal, i.v., dose 30-40 ml) according to body mass and the symptoms observed,--insertion of cannulas (o.d. 2.2 and i.d. 1.8 mm)--one into the jugular vein and the other into the caudal caval vein through the femoral vein. In several gilts the cannulas were inserted into the caudal caval vein to a depth of 14, 18, 20, 23, 25 and 30 cm from the femoral ring. The concentrations of progesterone (P4) and testosterone (T) were analysed in samples of blood plasma from the jugular and caudal caval veins by radioimmunoassay (RIA). The largest differences in hormone concentrations between the jugular and caudal caval veins were ascertained when a cannula was inserted into the caudal caval vein to a depth of 20 cm from the femoral ring. In other cases the differences were less prominent, or no differences were observed (e.g. 14 cm for progesterone and testosterone or 18 cm for testosterone).