Steroid production by amago salmon (Oncorhynchus rhodurus) testes at different development stages

Developmental changes in the steroidogenic capacity of amago salmon (Oncorhynchus rhodurus) testicular fragments at six different stages during spermatogenesis and spermiation were examined using 18-hr incubations. Although both basal and chum salmon gonadotropin (SGA)-induced production of 11-ketotestosterone (11-ketoT) and 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHprog) remained relatively low in testicular fragments isolated in August (GSI 1.06; primarily spermatocytes and spermatids in the testes) and September (GSI 2.33-4.85; many spermatids and spermatozoa in the testes), 11-ketoT production was two to three times higher than 17 alpha,20 beta-diOHprog production. In mid October (GSI 4.31; primarily spermatozoa in the testes, with a few spermatids remaining), SGA greatly stimulated 11-ketoT production with no further stimulation in late October (GSI 3.54; advanced spermiation). In contrast, SGA dramatically increased 17 alpha,20 beta-diOHprog production in late October and November (GSI 3.02), coincident with the period of active spermiation. A time course study showed that SGA caused a marked increase in production of 17 alpha,20 beta-diOHprog within the first 3 hr. Testes collected in August and September produced a considerable amount of 17 alpha,20 beta-diOHprog in the presence of an exogenous precursor, 17 alpha-hydroxyprogesterone. These results indicate that a shift in steroidogenesis from 11-ketoT to 17 alpha,20 beta-diOHprog occurs in the amago salmon testis immediately prior to or during the spermiation period and further suggest that mechanisms of gonadotropin action on 17 alpha,20 beta-diOHprog production in testes differ from those of ovaries (Y. Nagahama, 1987, Dev. Growth Differ. 29, 1-12).     

Chloride transport in primary cultures of rabbit colonocytes at different stages of development

BACKGROUND & AIMS: Ontogeny of colonic Cl- transport and its regulation has been characterized inadequately. The aim of this report was to study developmental changes in Cl- transport in primary cultures of rabbit distal colonocytes. METHODS: Colonocytes from newborn (7-9 days old), weanling (25-28 days old), and adult (6 months old) rabbits were cultured for 24 hours on a collagen IV matrix, and Cl- transport was measured using the fluoroprobe 6-methoxyquinolyl acetoethyl ester. RESULTS: Cl- permeabilities were dependent on [Cl-]o with maximal rates (in millimoles per liter per second) at [Cl-]o = 75 mmol/L (newborns; 0.15 +/- 0.04; weanlings; 0.2 +/- 0.02; and adults, 0.32 +/- 0.06). Influx was inhibited significantly by the Cl- channel (50 mumol/L diphenylamine-2-carboxylate) and the Na(+)-K(+)- 2Cl- cotransport (10 mumol/L furosemide) inhibitors. The adenosine 3',5'-cyclic monophosphate (cAMP)-dependent secretagogues, prostaglandin E1 (1 mumol/L), forskolin (1 mumol/L), and 8-bromo-cAMP (100 mumol/L), and the protein kinase C activator, phorbol 12-13 dibutyrate (1 mumol/L), increased Cl- influx significantly in all groups with adults showing greatest stimulation. However, taurodeoxycholate (0.025-1 mmol/L) had an effect only in the adult and the guanosine 3',5'-cyclic monophosphate (cGMP) activators STa and 8-bromo-cGMP had no effect. CONCLUSIONS: Rabbit distal colonocytes possess inhibitor-sensitive Cl- permeabilities even in neonates. However, the ontogeny of their regulation depends on the secretagogue-signaling pathway. (Gastroenterology 1996 Dec;111(6):1541-50)     

Water metabolism disturbances at different stages of primary thyroid failure

The aim of the present study was to study salt and water metabolism in thyroid deficiency. We performed an oral water loading test (OWL) and a hypertonic 5% saline infusion test (HSI) in 16 patients with overt primary hypothyroidism before replacement treatment (PRE group) and after, in eight patients with subclinical hypothyroidism (SUB group) and in 16 normal individuals (CG group). In the PRE group, a lower free water clearance was detected in the OWL (P < 0.022), with lower plasma osmolality (OWL: P < 0.005; HSI: P < 0.001) and arginine vasopressin (AVP) (OWL: P < 0.001; HSI: P < 0.001) than the CG group, across both tests; they normalized with the replacement treatment. The same plasma abnormalities were detected in the SUB group with the HSI. Although the AVP and thirst thresholds did not differ between the groups, the lag between them was lower in the PRE (4.1+/-3.2 mOsm/kg) and SUB group (2.6+/-2.1 mOsm/kg) than in the CG group (13.3+/-9.2 mOsm/kg) (P < 0.05). There were no differences in atrial natriuretic hormone (ANH), plasma renin activity (PRA) and plasma aldosterone among the groups. These results indicate that plasma hypo-osmolality and low levels of AVP are present in primary hypothyroidism, and indeed are already present in the subclinical phase of the disease. An overlap between the thresholds of thirst and AVP seem to play a role in these abnormalities, but ANH, PRA and plasma aldosterone do not appear to contribute.     

Progesterone metabolism in vitro in the decapod crustacean, Penaeus monodon.

Thin-layer chromatography (TLC) and reversed-phase high-performance liquid chromatography (RP-HPLC) with on-line detection of radioactive steroids were applied to identify metabolites of [4-14C]progesterone incubated in vitro with prawn ovary. There was extensive metabolism of progesterone by stage II (vitellogenic) ovary of Penaeus monodon. The most abundant metabolites were 5 alpha-pregnane derivatives together with two minor metabolites, 20 alpha-hydroxypregn-4-en-3-one and 1,4-pregnadiene-3,20-dione. In contrast, a much lower level of progesterone metabolism was observed in stage 0 (immature) ovary of this species. The hepatopancreas, gill, and abdominal muscle of P. monodon all metabolised [4-14C]progesterone to varying degrees, generating materials similar to those produced by the ovary. A comparative study of progesterone metabolism in stage II ovary of Nephrops norvegicus indicated that one metabolite, 20 alpha-hydroxypregn-4-en-3-one, was produced.     

Androgen biosynthesis by marmoset testes in vitro.

These studies were undertaken to determine the major steroid metabolites formed from selected androgen precursors by the testis of the marmoset, Saguinus oedipus, a New World primate of the family Callitricadae. Testicular fragments (50 mg) were incubated for 3.0 hr with pregnenolone-7-³H or with progesterone-7-³H. The major metabolites formed from pregnenolone were 17α-hydroxyprogesterone (42.7%), testosterone (20.5%), androstenedione (11.4%) and progesterone (9.2%). Nonmetabolized substrate was 6.8% of radioactivity. For porgesterone incubations, 17α-hydroxyprogesterone was the major matabolite (49.0%), with testosterone (21.2%) and androstenedione (10.7%) as lesser metabolites. Unreacted progesterone accounted for 14.9% of all radioactivity. The unusually high levels of 17α-hydroxyprogesterone in marmosets is in contrast to that observed in other mammalian species.     

不同糖代谢水平动态血糖谱的差异

目的研究不同糖代谢水平血糖谱差异,以便指导干预时机的选择。方法对糖耐量正常（NGT）、空腹血糖受损（IFG）、餐后血糖受损（IGT）、IFG＋IGT及新诊断T2DM患者的72小时动态血糖监测血糖谱进行分析。结果IFG＋IGT组血糖水平及血糖漂移显著高于NGT、IFG、IGT组（P〈0．05）。新诊断T2DM组血糖水平显著高于NGT、IFG、IGT、IFG＋IGT组（P均〈0．05）。新诊断T2DM组餐后及日内血糖漂移与IFG＋IGT组无显著差异（P〉0．05）。结论（1）随着糖代谢异常的加重,血糖水平升高,血糖漂移程度增加;（2）IFG＋IGT阶段应积极干预。     

Prolactin receptor on dissociated mammary epithelial cells at different stages of development.

Properties of prolactin receptors were measured by monitoring [125I]prolactin binding to specific receptor sites on collagenase-dissociated mammary epithelial cells of virgin, pregnant and lactating mice. On a Scatchard plot the data generated a straight line and the estimated dissociation constant (Kd) and number of receptor sites on lactating cells were 0.9 x 10(-9) and 1540 per cell. The [125I]prolactin binding was inhibited in presence of unlabeled prolactin and other lactogenic polypeptide hormones, but not by nonlactogenic polypeptide hormones. The [125I]prolactin binding was sensitive to pronase and trypsin but not to DNAase, RNAase and hyaluronidase. Scatchard plot analysis further showed that while the number of receptors on mammary cells was variable at different stages of endocrine regulated developmental changes of the gland, Kd of the hormone--receptor complex generally remained similar. The high level of prolactin receptors on mammary cells of virgins was reduced during pregnancy and the lactating mammary cells showed a highly elevated level of prolactin receptors. The results demonstrate that specific prolactin receptors can be measured on collagenase dissociated mammary epithelial cells and this method permits a direct assessment of the number of receptors on a per cell basis rather than indirect estimates, based on average DNA or protein content of the tissue, composed of heterogeneous cell types.     

Testosterone secretion by foetal rat testes in vitro.

Testosterone secretion by foetal rat testes (13 1/2-21 1/2 days of gestation) explanted for 3 days in a synthetic medium was measured every 24 h by radioimmunoassay. During the first day of explantation, the foetal testis produced, respectively, 1013 +/- 132, 8734 +/- 1118, 9179 +/- 2185 and 3886 +/- 309 (S.E.M.) pg/testis when explanted at 14 1/2, 16 1/2, 18 1/2 and 21 1/2 days respectively. Testosterone production by 13 1/2-day-old testes was not detectable on the first day of culture, but appeared on subsequent days. Daily testosterone secretion increased on the 2nd and 3rd days of culture in 14 1/2-day-old testes and decreased in older stages. These results suggest that the functional differentiation of the testis is independent of stimulatory factors like gonadotrophins. Dibutyryl cyclic AMP was found to stimulate testosterone production significantly from 14 1/2 days of gestation onwards.     

Androgen biosynthesis in vitro by testes from amphibia.

Testes from three species of anuran Amphibia, Bufo marinus, Rana catesbeiana, and Rana esculenta, were incubated with radioactive pregnenolone, progesterone, and testosterone. In all incubations the major metabolite was dihydrotestosterone, which accounted for 30–47% of the initial radioactivity after a 3-hr incubation. In addition, 5α-androstanedione and 5α-androstane-3β,17β-diol were formed from all three substrates with testes of Bufo marinus and Rana catesbeiana. Testes of Rana esculenta however converted only testosterone into 5α-androstanedione and 5α-androstanediol, pregnenolone and progesterone being transformed to 5α-pregnane-3β,17α,20ξ-triol. Since in both R. catesbeiana and B. marinus significantly higher yields of 5α-androgens were obtained from pregnenolone and progesterone than from testosterone, it is possible that at least some of these compounds arise from a biosynthetic pathway not involving testosterone.     

In vitro induced activity of polymorphonuclear leukocyte myeloperoxidase at different stages of opisthorchis invasion and at stages of a different rehabilitative period

Polymorphonuclear leukocytes from 115 patients with opisthrochiasis at its different (acute and chronic) stages were studied before and 1-3 days, 1-3 months, and 1-2 years after antihelminthic therapy with bilthricide. The functional activity of the cells in question was evaluated following an hour load with different drugs: bilthricide, ascorbic acid, decaris, cyclophosphane, doxycycline in a final concentration of 2.5 x 10(-5) mole/l. Physiological solution and autologous plasma were test controls. The changes in the activity of extracellular (secreted), intracellular (reserve), and summary myeloperoxidase on incubation with each test agent were found to depend on the stage of the disease and the interval after antihelminthic therapy. In early Opisthorchis invasion, the maximum increase in the induced activity of secreted myeloperoxidase is followed by a fall in the level of reserve myeloperoxidase in response to these drugs. With this, there is the most pronounced decrease in reserve myeloperoxidase of polymorphonuclear leukocytes in chronic opisthorchiasis, which may be due to the disrupted controlling processes of its production at late stages of the disease. The distinctive features of the action of agents on the overall activity of granular leukocytic myeloperoxidase in acute and chronic opisthorchiasis suggests that autologous plasma, ascorbic acid, and doxycycline should be used as a test control at the clinical stage of Opisthorchis invasion.     

Steroid biosynthesis in vitro by the gonads of Sparus auratus L. (Teleostei) at different stages during natural sex reversal

The metabolism in vitro of pregnenolone-4-¹⁴C by the gonads of Sparus auratus L., a protandrous hermaphroditic teleost, was studied during sexual maturity in the male and female phases and during sex reversal. Steroids were identified by their mobilities on thin-layer chromatograms, derivative formation, and recrystallization to constant specific activity, and their yield-time curves were plotted. Progesterone and 17α-hydroxyprogesterone were in every case the most abundant metabolites isolated, and the only ones identified in incubates with ovarian tissue during sex reversal. Some androstenedione was produced by mature testicular tissue, testicular tissue during reversal, and mature ovarian tissue, but only in the first case was there a significant further conversion to testosterone. Although estrogen production was always very small, estradiol-17β and estrone were isolated. Their formation was greater in mature ovarian tissue than in testicular preparations. The gonadal steroids of Sparus auratus L. do not seem to differ from those already described in various gonochoristic species. During sex reversal, gonadal steroid biosynthesis is probably at a minimum, with little interaction between the coexisting testicular and ovarian tissues.