EFFECT OF PERINATAL HYPOTHYROIDISM ON PITUITARY SECRETION OF GROWTH HORMONE AND PROLACTIN IN RATS

1974 ◽  
Vol 62 (2) ◽  
pp. 213-223 ◽  
Author(s):  
SAKAE KIKUYAMA ◽  
HIROSHI NAGASAWA ◽  
REIKO YANAI ◽  
KOREHITO YAMANOUCHI

SUMMARY Female Sprague—Dawley rats were fed 6-propyl-2-thiouracil (PTU) in their diet during late pregnancy and lactation. The growth and gonadal development of their pups were inhibited and in females the day of vaginal opening and onset of oestrous cycles were delayed; thyroid glands were hypertrophied. Treatment of the pups with thyroxine largely reversed these changes. The effect on body weight persisted even after treatment with PTU had stopped. At 20 days of age, the anterior pituitary glands of the pups of PTU-treated mothers contained significantly less growth hormone (GH) and prolactin than those of normal pups of both sexes. These changes persisted at 60 days of age. If the pups of PTU-treated mothers were given thyroxine from day 1 to day 20 of age, pituitary GH and prolactin content on day 20 had returned towards normal values. Thyroid deficiency was found to suppress the synthesis and release of prolactin and the synthesis of GH by the pituitary in vitro. These findings suggest that thyroxine influenced the maturation of the pituitary directly and/or through the hypothalamus and that thyroxine deficiency in early life brought about persistent alteration of the pituitary secretion of GH and prolactin.

1965 ◽  
Vol 49 (1) ◽  
pp. 1-16 ◽  
Author(s):  
M. Apostolakis

ABSTRACT A method for the extraction of prolactin from human pituitary glands is described. It is based on acetone drying, distilled water extraction, acetone and isoelectric precipitation. Two main products are obtained: Fraction R8 with a mean prolactin activity of 12.2 IU/mg and fraction U8 with a mean prolactin activity of 8.6 IU/mg. The former fraction does not contain any significant gonadotrophin activity and the latter contains on an average 50 HMG U/mg. In both cases contamination with ACTH and MSH is minimal. The growth hormone activity of both these fractions is low. It is postulated that in man too, prolactin and growth hormone are two distinct hormones. A total of 1250 human pituitary glands have been processed by this method. The mean prolactin content per pituitary gland has been found to be 73 IU.


1974 ◽  
Vol 75 (4) ◽  
pp. 669-682 ◽  
Author(s):  
K.-G. Thorngren ◽  
L. I. Hansson

ABSTRACT The growth stimulating effect of growth hormone was determined with tetracycline as intravital marker of the longitudinal bone growth of proximal tibia in female Sprague-Dawley rats hypophysectomized at 60 days of age. After a post-operative control period of 15 days growth hormone (NIH-GH-B16) was given daily for 5 or 10 days followed by a 10 day period after its withdrawal. L-thyroxine was given in association with the growth hormone administration to potentiate the growth stimulation. A linear log dose-response relation was found for the two administration models with a high precision. The thyroxine-treatment increased the sensitivity of the bioassay. An administration period of 5 days was found sufficient for the bioassay of growth hormone in thyroxine-treated hypophysectomized rats. Compared with the earlier bioassay methods for growth hormone, the present bioassay is more favourable when all the factors, such as precision, sensitivity, specificity, and administration period are considered.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Himanshu Kushwah ◽  
Nidhi Sandal ◽  
Meenakshi Chauhan ◽  
Gaurav Mittal

Abstract Background Uncontrolled bleeding is one of the primary reasons for preventable death in both civilian trauma and military battle field. This study evaluates in vitro and in vivo hemostatic potential of four biopolymeric natural gums, namely, gum tragacanth, guar gum, xanthan gum, and gum acacia. In vitro evaluation of whole blood clotting time and erythrocyte agglutination assay were carried out. In vitro cytotoxicity studies with respect to each gum were done in human lymphocytes to ascertain percent cell viability. In vivo hemostatic potential of each gum (as sponge dressing and powder form) was evaluated in Sprague Dawley rats using tail bleeding assay and compared with commercially available hemostatic sponge. Other important parameters like (a) time taken for complete hemostasis, (b) amount of blood absorbed, (c) adherence strength of developed hemostatic dressing(s), (d) incidence of re-bleeding, and (e) survival of animals were also studied. Results Of the four test gums studied, xanthan gum (@3mg/ml of blood) and gum tragacanth (@35mg/ml of blood) were able to clot blood in least time (58.75±6.408 s and 59.00±2.082 s, respectively) and exhibited very good hemostatic potential in vitro. Except for xanthan gum, all other test gums did not exhibit any significant cytotoxicity at different time points till 24 h. In rat tail bleeding experiments, gum tragacanth sponge dressing and powder achieved hemostasis in least time (156.2±12.86 s and 76±12.55 s, respectively) and much earlier than commercially available product (333.3±38.84 s; p˂0.01). Conclusion Results indicate potential of gum tragacanth to be developed into a suitable hemostatic product.


1973 ◽  
Vol 134 (4) ◽  
pp. 1103-1113 ◽  
Author(s):  
A. Betteridge ◽  
M. Wallis

The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2μm (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1–5μm-insulin (140–700munits/ml). Lower more physiological concentrations had no significant effect in this system. Above 10μm (1.4 units/ml) total protein synthesis was also increased. The stimulation of growth hormone synthesis could be partially blocked by the addition of actinomycin D, suggesting that RNA synthesis was involved. Insulin was found to stimulate the rate of glucose utilization in a similar way to growth hormone synthesis. 2-Deoxyglucose and phloridzin, which both prevented insulin from stimulating glucose utilization, also prevented the effect of insulin on growth hormone synthesis. If glucose was replaced by fructose in the medium, the effect of insulin on growth hormone synthesis was decreased. We conclude that the rate of utilization of glucose may be an important step in mediating the effect of insulin on growth hormone synthesis.


1991 ◽  
Vol 7 (3) ◽  
pp. 125-139 ◽  
Author(s):  
David R. Bevan ◽  
David M. Ruggio

To evaluate health risks associated with exposure to particulates in the environment, it is necessary to quantify the bioavailability of carcinogens associated with the particulates. Direct analysis of bioavailability in vivo is most readily accomplished by adsorbing a radiolabeled form of the carcinogen to the particulate. A sam ple of native diesel particulate collected from an Oldsmobile die sel engine that contained 1.03 μ g benzo[ a] pyrene ( BaP)/ g particulate was supplemented with exogenous [ 3 H]- BaP to pro duce a particulate containing 2.62 μ g BaP/g. To insure that elu tion of BaP from native and [3 H] -BaP-supplemented particulate was similar, in vitro analyses were performed. When using phos pholipid vesicles composed of dimyristoylphosphatidylcholine (DMPC), 1.52% of total BaP was eluted from native particulate into the vesicles in 18 hrs; from [ 3 H] -BaP supplemented particu late, 1.68% was eluted. Using toluene as eluent, 2.55% was eluted from native particulate, and 8.25% from supplemented particulate, in 6 hrs. Supplemented particulate was then instilled intratracheally into male Sprague-Dawley rats and distribution of radioactivity was analyzed at selected times over 3 days. About 50% of radioactivity remained in lungs at 3 days following instil lation, with 30% being excreted into feces and the remainder dis tributed throughout the organs of the rats. To estimate the amount of radioactivity that entered feces through swallowing of a portion of the instilled dose, [3 H] -BaP-supplemented particu late was instilled intratracheally into rats that had a cannula sur gically implanted in the bile duct. Rate of elimination of radio activity into bile was monitored; 10.6% of radioactivity was re covered in 6 hr, an amount slightly lower than the 12.8% ex creted in 6 hrs into feces of animals with intact bile ducts. Our studies provide a quantitative description of the distribution of BaP and its metabolites following intratracheal instillation of diesel particulate. Because rates of elution of BaP in vitro are similar for native diesel particulate and particulate with supple mental [ 3H] -BaP, our results provide a reasonable estimate of the bioavailability in vivo of BaP associated with diesel particu late.


2002 ◽  
Vol 291 (3) ◽  
pp. 722-726 ◽  
Author(s):  
Stephen E. Borst ◽  
Harold G. Snellen ◽  
Henry Ross ◽  
Philip J. Scarpace ◽  
Yong-Woon Kim

2013 ◽  
Vol 32 (5) ◽  
pp. 385-394 ◽  
Author(s):  
Antoinette Y. Odendaal ◽  
Narendra S. Deshmukh ◽  
Tennille K. Marx ◽  
Alexander G. Schauss ◽  
John R. Endres ◽  
...  

This toxicological assessment evaluated the safety of a hydroethanolic extract prepared from Caralluma fimbriata (CFE), a dietary supplement marketed worldwide as an appetite suppressant. Studies included 2 in vitro genotoxicity assays, a repeated dose oral toxicity study, and a developmental study in rats. No evidence of in vitro mutagenicity or clastogenicity surfaced in the in vitro studies at concentrations up to 5000 μg of extract/plate (Ames test) or 5000 μg of extract/mL (chromosomal aberration test). No deaths or treatment-related toxicity were seen in the 6-month chronic oral toxicity study in Sprague-Dawley rats conducted at 3 doses (100, 300, and 1000 mg/kg body weight (bw)/d). The no observed effect level for CFE in this study was considered to be 1000 mg/kg bw/d. A prenatal developmental toxicity study conducted at 3 doses (250, 500, and 1000 mg/kg bw/d) in female Sprague-Dawley rats resulted in no treatment-related external, visceral, or skeletal fetal abnormalities, and no treatment-related maternal or pregnancy alterations were seen at and up to the maximum dose tested. CFE was not associated with any toxicity or adverse events.


1993 ◽  
Vol 41 (1) ◽  
pp. 141-147 ◽  
Author(s):  
Amy G. Hackett ◽  
John J. Kotyk ◽  
Hideji. Fujiwara ◽  
Eugene W. Logusch

Author(s):  
Nurarita Fadila Zesiorani ◽  
Effionora Anwar

Objective: This study aims to formulate and characterize a transfersome apple peel extract, formulate it into a gel, and compare it with a control gelmade without transfersome.Methods: Both gels were evaluated, stability tested, and penetration tested using Franz diffusion cells on the skin of female Sprague-Dawley rats. Thetransfersome preparations were formulated with different concentrations of the active substance, quercetin: 0.5% (F1); 0.7% (F2), and 1.0% (F3).Results: Based on the characterization results, F1 was selected as the optimum gel formulation because it had spherical morphology, a Dmean volume of106.44±2.70 nm, a polydispersity index of 0.078±0.01, a zeta potential of −49.96±2.05 mV, and a drug efficiency entrapment percentage of 78.78±0.46%.The cumulative amount of quercetin that was penetrated with the transfersome gel was 1514.41±26.31 μg/cm2, whereas the penetration with thecontrol gel extract was 1133.62±18.96 μg/cm2. The cumulative percentages of the penetrated gel transfersome and gel extract were 78.40±1.89%and 49.89±0.88%, respectively. The fluxes of transfersome gel and control gel extract were 52.33±0.11 μg/cm²/hrs and 40.89±0.68 μg/cm²/hrs,respectively.Conclusions: Based on these results, it can be concluded that the gel with transfersome exhibited better penetration than the gel extract alone.


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