Effects of pregnenolone, cyclic adenosine monophosphate, and human chorionic gonadotropin on in vitro progesterone and estrone synthesis by the porcine placenta and endometrium.

Two experiments were conducted to determine the effects of pregnenolone (P5), cyclic adenosine monophosphate (cAMP), and human chorionic gonadotropin (hCG) on porcine placental and endometrial production of progesterone (P4) and estrone (E1) in vitro at days 30, 60 and 90 of gestation. Placental P4 production increased between days 30 and 90 and was enhanced by the addition of P5. A further increase in placental P4 production occurred at days 30 and 90 due to cAMP supplementation. Addition of hCG failed to increase placental P4 production at any day. Placental E1 production in vitro was biphasic and mimicked the pattern seen in maternal plasma and fetal fluids. Placental E1 production in P5-supplemented medium was enhanced by the addition of cAMP at day 90. However, hCG supplementation reduced placental E1 production at day 90. Endometrial P4 and E1 production were similar to those of the placenta at day 30 of gestation. However, unlike placental steroidogenesis, endometrial hormone production remained relatively constant over the 3 days of gestation examined. Supplemental P5 enhanced endometrial P4 and E1 production. The overall magnitude of response to supplementation was considerably less in endometrial vs placental tissue. We conclude that both porcine placental and endometrial tissues are steroidogenically competent but that placenta is the far more active and responsive tissue. The mechanism controlling placental steroidogenesis apparently does not involve LH/hCG tropic stimulation, but cAMP is an effective intracellular second messenger.

[Bone density in idiopathic hypercalciuria in men. Study by dual photon absorptiometry, X-ray computed tomography and histomorphometry]. / La densité osseuse dans l'hypercalciurie idiopathique chez l'homme. Etude par absorptiométrie biphotonique, tomodensitométrie et histomorphométrie.

Lumbar bone mineral density (BMD) of the L3 vertebra was evaluated by double photon absorptiometry or tomodensitometry (TDM) in 55 hypercalciuric individuals in two separate studies. In the first, in a department of nephrology, 29 lithiasis patients were studied by TDM of L3. By this technique, trabecular density was 75 +/- 23% of normal. It was lower in the 17 patients in whom hypercalciuria persisted after calcium restriction (66 +/- 15% of normal and below the "fracture threshold" in 9 cases) than in the 12 patients in whom it disappeared after the prescription of such a diet (88 +/- 26%, below the "fracture threshold" in 3 cases), this difference being significant (p less than 0.01). In another 26 patients, seen in a department of rheumatology, three of whom had osteoporosis with vertebral fracture, density was measured in 21 cases by double photon absorptiometry (mean Z score -1.9 +/- 1.0) and in 5 cases by TDM (mean BMD of L3 69 +/- 21% of normal). Mean iliac trabecular volume, measured in 8 cases only, was 70 +/- 25% of normal and was below the "fracture threshold" in 3 cases. Comparison of the two study groups was not possible because of differences in recruitment and methods of investigation. These two studies nevertheless show the existence of significant vertebral bone rarefaction during hypercalciuria in the young man. Confirmed and quantified in patients in whom the metabolic disturbance was discovered as a result of radiological abnormalities, this quantitative abnormality was also seen in patients in whom hypercalciurie was found because of renal lithiasis.(ABSTRACT TRUNCATED AT 250 WORDS)