Prostaglandin D2 is the major prostaglandin of arachidonic acid metabolism in rat bone marrow homogenate

Homogenate of bone marrow of male rat was incubated with 14C-arachidonic acid and with 14C-prostaglandin H2. The major prostaglandin produced during each incubation was prostaglandin D2, which was identified by thin-layer chromatography, autoradiography and chemical reduction.

Low serum estradiol levels in subjects with arterial calcification

The relationship between arterial calcification and serum estradiol levels was studied in 72 postmenopausal female and 59 male subjects. In both sexes, subjects with iliac artery calcification had rather lower serum estradiol levels (8.4 +/- 1.4 pg/ml in the females, and 19.2 +/- 2.5 pg/ml in the males) than controls (16.1 +/- 1.6 pg/ml in the females, and 29.7 +/- 2.4 pg/ml in the males). The bone mineral content of females with iliac artery calcification (0.44 +/- 0.02 g/cm2) was lower than controls (0.52 +/- 0.01 g/cm2); a positive correlation between serum estradiol levels and bone mineral content was found in the females. However, bone mineral content did not significantly differ between males with and without arterial calcification (0.67 +/- 0.03 g/cm2 in the former, and 0.65 +/- 0.02 g/cm2 in the latter). These results indicate that arterial calcification and increased bone resorption are both individual results of estrogen deficiency.

Serum estradiol and radial mineral content in postmenopausal females

The serum estradiol concentration and bone mineral content of the right radius were determined in 34 postmenopausal females. Regression analysis showed a significant positive correlation between the serum estradiol concentration and bone mineral content of the right radius (r=0.477, p less than 0.01). These results support the view that the decreased level of serum estrogens is one of the major factors involved in the loss of bone mass with age.

Immunological stability in vitro and in vivo of eel calcitonin

The immunological activity of eel calcitonin was more persistent than that of porcine and human calcitonin when incubated in vitro with rabbit serum, human serum, liver homogenate or kidney homogenate, respectively. Both eel and human calcitonin were more stable than porcine calcitonin when injected iv into rabbits.

Stability of [Asu1,7]-eel calcitonin and eel calcitonin in vitro and in vivo

Stability of [Asu1,7]-eel calcitonin was compared with that of eel calcitonin by the radioimmunoassay method. [Asu1,7]-Eel calcitonin cross-reacted with anti-eel calcitonin antisera. [Asu1,7]-Eel calcitonin was as stable as eel calcitonin in rabbit liver or rabbit kidney extracts when incubated at 37 degrees C. Disappearance curves from the plasma of [Asu1,7]-eel calcitonin and eel calcitonin following iv injection in rabbits were quite similar.

Extraction and partial purification of prolactin-release stimulating factor in bovine hypothalami

Partial purification of prolactin-release stimulating factor (PRF) was performed by Sephadex G-25 gel filtration of bovine hypothalamic extracts. PRF activity was evaluated on the basis of the measurement of immunoreactive prolactin released from the isolated rat hemipituitary in vitro. PRF activity was found in the fractions with Kav=0-0.49 and prolactin-release inhibiting activity was also detected in the fractions with Kav=0.69-0.89. The dose-response relationship was established between the partially purified PRF and its activity. The elution position of the partially purified PRF preceded that of TRH on Sephadex G-25. TRH at the dose of 100 nM stimulated the release of TSH in vitro, but not the release of prolactin. These results may indicate that there exists PRF with a relatively high molecular weight in the bovine hypothalamus.