Stabilization of steroid 11-hydroxylation activity ofCunninghamella elegans protoplasts in organic osmotic stabilizers

Protoplasts ofCunninghamella elegans, showing 11-, and 11-hydroxylating ability of Substance S, preserved high transformation activity when dispersed in glucose-enriched, organic osmotic stabilizers. A joint action of polyoxins and 2-deoxy-d-glucose was necessary to prevent regeneration of the cell wall in long-lasting experiments. Stabilized and active, dispersed protoplasts may be an alternative research model for studying the function of the cell wall and intracellular metabolic pool constituents in steroid hydroxylation.     

Identification and characterization of a pregnane steroid recognition site that is functionally coupled to an expressed GABAA receptor

Conclusion Based on the pharmacological and biochemical evidence to date, especially that derived from the recombinantly expressed receptor studies, the suggestion that a novel GBRC-linked steroid recognition site exists becomes a cogent argument. The high affinity of the steroid site for certain naturally occurring metabolites of progesterone and glucocorticoids favors a physiologic role for these steroids in the regulation of brain excitability. Clearly, investigations of such a regulatory role is warranted. If present, it provides an important example of endocrine control of a major inhibitory neurotransmitter in the CNS. Moreover, as we gain a greater understanding of the molecular organization of the GBRC, the putative steroid site provides a novel target for the rational design of therapeutic agents for the treatment of anxiety, epilepsy, and insomnia.Special issue dedicated to Dr. Eugene Roberts.     

Dermorphin decreases plasma LH levels in human: evidence for a modulatory role of gonadal steroids

The purpose of this study was to evaluate the effects of dermorphin, a new synthetic powerful opiate-like heptapeptide, on plasma luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels in fertile and postmenopausal women. In fertile subjects, dermorphin (5.5 micrograms/kg min for 30 min) decreases plasma LH (p less than 0.01 vs. baseline and placebo values), but not plasma FSH. The area under the curve during dermorphin infusion was significantly lower than during placebo infusion (p less than 0.01). Pretreatment with the opioid receptor antagonist naloxone, blocked the decrease of plasma LH levels. In postmenopausal women not subjected to any treatment, dermorphin infusion did not significantly modify plasma LH and FSH levels. On the contrary, its administration to postmenopausal subjects treated with conjugated estrogens and medroxyprogesterone acetate significantly decreased plasma LH levels (p less than 0.01, vs. baseline, placebo and area under the curve). Considering the modulatory role exerted by ovarian steroids on the activity of such receptors, these data also indicate that opioid systems play a very important part in the hypothalamus-pituitary-ovarian axis.     

Blood typing invalidates alleged evidence of fertility of XO mare

A mare with XO gonadal dysgenesis was reported to have produced two foals. Blood samples from the mare, her two foals, their sire and the mare's sire were typed for blood-group and serum protein variants in conjunction with registry requirements. Both foals qualified as offspring of the reported parents. However, the blood-typed mare could be excluded as an offspring of her alleged sire. An alternative hypothesis to explain the blood-type and karyotype findings was that a fertile mare had been substituted for the XO mare, as surrogate mother and blood-type donor. A computer search of 120,000 blood-type records identified only one other horse with the same blood type as the dam of the foals. That horse was a mare of the same breed and owned by the person who had attempted to register foals from the XO mare. These blood-type findings invalidated the allegation of XO fertility and emphasize the need for parentage verification to support reports of unusual reproductive performance.     

Different hormonal requirements for androgen-independent growth of normal and tumor epithelial cells from rat prostate

Summary The proliferation of isolated normal prostate epithelial cells from rat and man is androgen-independent and requires cholera toxin, insulin, dexamethasone, epidermal growth factor (EGF) and one or more polypeptide factors that are concentrated in bovine neural tissue. The active agents in the neural tissue extract are heparin-binding polypeptides (prostatropins), the predominant form of which has a molecular weight of 17400 and an acetylalanine at the aminoterminus. Prostatropins supported a half-maximal increase in normal prostate epithelial cell number at 50 picomolar. The proliferation of primary and serially-cultured epithelial cells from androgen-responsive Dunning R3327 rat prostate tumors was also androgen-independent, but exhibited dramatic alterations in response to hormones that stimulated normal cell proliferation. At low cell density, androgen-independent growth of isolated tumor-derived epithelial cells was independent on cholera toxin, was stimulated by dexamethasone, required insulin andeither EGFor prostatropin. The presence of either EGF or prostatropin masked the response to the other factor. In the absence of EGF, purified prostatropins supported a half-maximal increase in tumor cell number at 7 picomolar. Endogenous production of EGF-like and prostatropin-like factors or both was suggested by the reduced requirement for EGF and prostatropin at high prostate tumor cell density. These results suggest that anti-hormonal therapies against prostate tumor growth should be based on intervention with the activity of insulin (or insulin-like factors) or simultaneous intervention with both EGF and prostatropin (or their homologues). This work was supported by NIH grants CA 37589 and HL 33847, and grant 1718 from the Council for Tobacco Research. Editor’s Statement This paper is the first report of the comparison of the hormone requirements of primary cultures of normal and tumor prostate epithelial cells from the same system.     

Effects of superovulatory doses of pregnant mare serum gonadotropin on oocyte quality and ovulatory and steroid hormone responses in rats

Immature rats (aged 28 days) were injected with 4, 20, or 40 IU pregnant mare serum gonadotropin (PMSG) and sacrificed every 6 or 12 hr. Control rats (4 IU) ovulated between 60 and 72 hr, whereas rats given superovulatory doses of PMSG (20 and 40 IU) ovulated between 24 and 72 hr. The oocyte count from the superovulated rats increased slightly between 24 and 36 hr and markedly between 48 and 72 hr. Degenerated oocytes were recovered 48 and 36 hr after administration of 20 and 40 IU PMSG, respectively. Thereafter, the proportion of degenerated oocytes was dose dependent and reached a maximum at 72 (30.9%, 20 IU) and 60 hr (61.0%, 40 IU). 17β-estradiol content of the superovulated ovaries increased significantly (P < 0.01) from 36 hr and was maximal at 60 (20 IU) or 54 hr (40 IU), when compared to the control regimen. Administration of 40 IU PMSG resulted in a biphasic increase of progesterone content with the peaks at 36 and 60 hr. Androgen content of the superovulated ovaries was lower than control levels during the first 36 hr but was significantly (P < 0.01) higher thereafter. The results suggest that these alterations in the steroid response (particularly androgens) from 36 hr onward following superovulation may be responsible for the coincidental occurrence of abnormal oocytes, possibly by disturbing the specific intrafollicular steroid environment essential for complete maturation. In addition, oocyte aging that is due to earlier activation by the exogenous luteinizing hormone activity may be a contributing factor.     

Monitoring ovulation and implantation in the cynomolgus macaque (Macaca fascicularis) through evaluations of urinary estrone conjugates and progesterone metabolites: a technique for the routine evaluation of reproductive parameters

Investigations were undertaken to determine the applicability of recently reported specific radioimmunoassays for urinary estrone conjugates and progesterone metabolites for monitoring ovarian function in the cynomolgus macaque (Macaca fasciularis) and other macaque species. Mean estrone conjugate measurements appear to accurately reflect the preovulatory estrogen peak in both conceptive (n = 5) and nonconceptive (n = 6) cycles, as well as to indicate early pregnancy through increases which are significantly elevated by Day + 15 (p less than 0.049) post estrone conjugates peak. The mean luteal phase levels of these progesterone metabolites are significantly elevated by Day + 14 (p less than 0.012) in conceptive cycles when compared to the mean values for nonconceptive cycles.     

Induction of sexual reproduction in Opalina sudafricana by injecting its host Bufo regularis with gibberellic acid

Induction of sexual reproduction in Opalina sudafricana by injecting its host Bufo regularis with gibberellic acid. International Journal for Parasitology4, 203–206. Opalina sudafricana parasitic in the rectum of Bufo regularis was induced to reproduce sexually when its host was injected subcutaneously with 0·3 mg of gibberellin-A₃. This plant growth substance had no effect on the induction of encystation in the parasites in vitro. Urine of toads injected with gibberellin-A₃ induced sexual reproduction (encystation) in the opalinids in vitro. It is speculated that the plant hormone must either be broken down into an active substance by the toad or cause the toad to excrete its own gonadal hormones (or other hormones) into the urine. This active substance or the excreted hormones may induce division in the parasites resulting in the formation of small forms which encyst.     

Anatomical distribution of NADPH-cytochrome P450 reductase and cytochrome P4502D forms in rat brain: Effects of xenobiotics and sex steroids

Since the brain is not a homogeneous organ, but one dependent upon the well orchestrated interaction of numerous parts, pathology in one nucleus may have a large impact upon its overall function. Hence, the anatomical distribution of the P450 monoxygenase system in brain, as well as the regulation of its expression, is important in elucidating its function in that organ. In order to study these issues, female rats-both ovariectomized and not-were treated with a number of xenobiotic compounds and sex steroids. The brains from these animals were dissected into 8 discrete regions and the presence and relative level of message for P4502D and P450 reductase determined using polymerase chain reaction. Results of this investigation indicate the presence of mRNA for reductase and P4502D isoforms throughout the rat brain. In addition, quantitative PCR was utilized to demonstrate the effects of xenobiotics (phenobarbital, β-naphthoflavone, imipramine) and sex hormones (testosterone, estrogen) on the levels of these messages in the female rat brain. Significant induction of message for P4502D forms was noted with testosterone in the absence of estrogen. The level of mRNA for reductase was not significantly influenced by any of the treatments, however. These results raise the issue of a sexual dimorphism in the rat regarding P4502D expression in brain.