The mechanism of hormonal receptor regulation in the rat ovary following administration of gonadotropin and prolactin

In order to understand the role of hormonal receptors in patients with hyperprolactinemia, changes in the ovarian receptors for prolactin and LH and in the serum hormone levels were studied in mature female rats. Wistar-Imamichi strain rats were pretreated with ovine prolactin (oPRL; 1IU), hCG (10IU) or hMG (20IU) for 4 days and oPRL, hCG, oPRL plus hCG for 8 days. The ovarian LH receptor levels fell significantly in rats stimulated with hCG, oPRL or hCG plus oPRL for 4 or 8 days. The serum estradiol level rose with hCG, and fell with oPRL. Combined treatment with oPRL and hCG synergistically reduced LH receptor to below the control level, and the estradiol level near the control compared with that by hCG alone. A decrease in LH receptor (60%) after the 4-day treatment with oPRL was further lowered to 53% of the control level after the 8 day treatment. Prolactin receptor levels rose with hCG after the 4-day administration, and then returned to normal after the 8-day treatment. The hMG treatment for 4 days raised the serum estradiol and progesterone levels to 9 times and twice those of the controls, respectively, without changing ovarian receptor levels. Prolactin seems to lower the ovarian LH receptor levels under certain conditions, and this may be one of the causes of the refractory reaction to gonadotropin therapy in patients with hyperprolactinemia.     

Avian retrovirus S13: properties of the genome and of the transformation-specific protein

The avian retrovirus S13 codes for an env-linked transformation-specific glycoprotein with a molecular weight of 155,000 (gp155). Treatment of gp155 with endoglycosidase H or growth of S13-infected cells in the presence of tunicamycin reduces the molecular weight of gp155 to about 140K, but these gp155-related molecules may still contain sugar residues. The gp155 protein is not incorporated into virions; it is phosphorylated, but in immunoprecipitates does not show protein kinase activity. The genome of S13 is an 8.5-kilobase (kb) RNA; the helper virus genome is 7.5 kb in size. The putative onc sequences of S13 do not hybridize to DNA probes representing src, erb A, erb B, myc, myb, fps, fms, H-ras, B-lym, abl, rel, and ets.     

Abdominal tuberculosis: CT evaluation

The computed tomography (CT) scans of 27 patients with abdominal tuberculosis were reviewed retrospectively to determine the range of abdominal involvement. Most patients had been at increased risk because of intravenous drug abuse, alcoholism, acquired immunodeficiency syndrome (AIDS), cirrhosis, or steroid therapy. The etiologic agent was Mycobacterium tuberculosis in 23 patients and M. avium-intracellulare in four patients with AIDS. In five patients, tuberculosis was limited to the abdomen. CT findings included adenopathy, splenomegaly, hepatomegaly, ascites, bowel involvement, pleural effusion, intrasplenic masses, and intrahepatic masses. Characteristic features were a tendency for adenopathy to prominently involve peripancreatic and mesenteric compartments, low-density centers within enlarged nodes, complex nature of the ascites, and adenopathy adjacent to sites of gastrointestinal tract involvement. Recognition of these manifestations and maintenance of an index of suspicion, especially in patients at risk, should help optimize the correct diagnosis and management of intraabdominal tuberculosis.     

Ovarian membrane receptors for LH, FSH and prolactin during the menstrual cycle and in polycystic ovary syndrome

To investigate the role of ovarian membrane receptors for LH, FSH and prolactin of patients with developing polycystic ovary (PCO) syndrome, seven patients were selected and the receptor function was studied in relation to changes of several serum hormone levels. The results were compared with those from individuals with regular menstrual cycles in the late follicular (LF; n = 6) and midluteal (ML; n = 6) phases. LH receptor binding in the normal cycle remained low (1.73 +/- 0.14 fmole/mg homogenate protein) in the LF phase and elevated 3 fold in the ML phase. LH receptors in the PCO patients maintained a higher binding level than that in the LF phase, being close to the ML level. FSH receptors were at a high level in the LF phase (4.09 +/- 0.40 fmole/mg homogenate protein), but decreased by 23% in the ML phase. In the PCO group the ovarian FSH receptor showed a high level, near to that in the LF phase. Prolactin receptors showed no significant changes among the two controls and PCO group. PCO patients showed increased levels of serum LH and testosterone and a raised ratio of estrone to estradiol, although there was no change in the serum FSH level. These data suggested that the LH receptor binding in PCO was not so low as to the LF level. A lack of the down-regulation mechanism of LH receptors, in spite of the high level of serum LH in PCO, might be one of the clues to elucidate the pathophysiological mechanism in developing PCO syndrome. Elevated levels of the gonadotropin receptors, especially FSH receptors, seem to be involved in the high incidence of ovarian hyperstimulation during hormone treatment.     

Maximization of contrast-to-noise ratio to distinguish diffusion and microcirculatory flow.

Optimization of the contrast-to-noise ratio (CNR) is described for microcirculation magnetic resonance (MR) imaging techniques based on flow-compensated/flow-dephased sequences, both with and without even-echo rephasing. The authors present the most advantageous manner of applying flow-dephased gradients, such that dephasing is maximal while diffusion losses are minimal. The theoretical considerations include phase, diffusion, echo time, and bandwidth in the determination of the optimal parameters for microcirculation imaging. Studies in phantoms consisting of stationary and flowing copper sulfate in Sephadex columns demonstrate the validity of the calculations. Optimized in vivo images of a rat stroke model demonstrate the potential of the flow-compensated/flow-dephased technique and the importance of optimizing CNR.     

Actions of antisecretory agents on proton transport in hog gastric microsomes

The properties of K+-stimulated ATP hydrolysis (K+-ATPase) and vesicular accumulation of H+ (H+ accumulation) in hog gastric microsomes were investigated. The microsomes consisted of smooth surfaced vesicular particles, 70-300 nm in diameter. Both the activities of ATPase and the vesicular accumulation of H+ were stimulated by K+ in the presence of Mg2+, and enhanced by the K+-ionophore, valinomycin. However, there were differences in regulation of K+-ATPase and H+ accumulation by K+ ions, i.e. K+ at concentrations higher than 10 mM decreased K+-ATPase activity but further enhanced H+ transport. This observation suggests that the two reactions are partly independent. The H+ accumulation was inhibited by omeprazole, fenoctimine, spermine, and NaSCN, but not by cimetidine, prostaglandin E2, and atropine. The inhibitory effect of omeprazole on H+ accumulation paralleled the inhibition of K+-ATPase, while fenoctimine, spermine, and NaSCN suppressed H+ accumulation, without inhibiting K+-ATPase, under appropriate concentrations. In addition, the spontaneous diffusion of H+ across the microsomal membrane was markedly enhanced by fenoctimine, but not by the other agents used. These results indicate that omeprazole inhibits H+ accumulation by inhibiting K+-ATPase, fenoctimine suppresses H+ accumulation mainly by increasing the loss of accumulated H+ from the microsomal vesicles, spermine and NaSCN reduce H+ accumulation by inhibiting the transport of H+ into microsomal vesicles.