Combined ACTH and glucocorticoid treatment improves survival and organ maturation in premature newborn calves.

With the material of Chap 1 as background, this chapter discusses the effects of in vivo glucocorticoid treatment on lung maturation This topic has been the subject of numerous reviews over the past 15 years These include articles and chapters by Avery (1975), Taeusch and Avery (1977), Gross (1977), Hallman and Gluck (1977), Brown et al (1978), Farrell and Hamosh (1978), Ballard (1979), Rooney (1979), Batenburg and Van Golde (1979), Olson (1979), Smith and Bogues (1979), Hitchcock (1980), Ballard (1982), Possmayer (1982), Ballard (1983), Rooney (1983) and Smith (1984) Rather than providing a detailed accounting of all of the numerous contributions in the literature on this topic, this chapter summarizes the different types of experimental approaches and the various effects observed with in vivo corticosteroid treatment Other aspects of corticosteroids and lung maturation are discussed in subsequent chapters Responses of lung tissue in culture are included in Chap 3, 4, 9, and 10 Chapter 4 is devoted to the role of endogenous corticosteroids in lung maturation, and includes experiments employing ablation and replacement therapy Thus, this chapter is restricted to a summary of in vivo glucocorticoid treatment of the intact fetus with only occasional references to in vitro systems for comparison

Glucocorticoid Effects in Vivo

Ovine embryos collected from two breeds of ewes possessing different gestational periods [Finnish Landrace (Finn), 145.5 +/- 1.4 days; Rambouillet (Ra), 150.7 +/- 1.3 days] were transferred to common, randomly selected recipients. Fetal plasma samples were collected from mixed-breed (MB, one Finn and one Ra; n = 6) and single-breed (SB, single Finn, n = 3; single Ra, n = 3) chronic fetal preparations during the last trimester. In the MB pregnancy, the Ra sibling had temporal patterns of androstenedione similar to those observed in the Finn co-twin; however, these particular changes were greatly accelerated in comparison to the same day of gestation in SB Ra fetuses. Similarly, temporal patterns of change in unconjugated estrone, estrone sulfate, and 17 beta-estradiol were accelerated by as much as 4.6 to 5 days in Ra fetuses of MB pregnancies when compared to Ra fetuses in the SB pregnancies (P less than 0.001), with no difference noted between Ra and Finn co-twins. Maternal progesterone concentrations changed from 8 to 2 ng/ml, androstenedione from 200 to 400 pg/ml, estrone from 65 to 250 pg/ml, and 15-keto-13,14-dihydroprostaglandin F2 alpha from 200 pg/ml to 6000 pg/ml over the last 4 or 5 days of gestation. Chronic fetal manipulation accelerated parturition, with mean gestational lengths in MB, SB Finn, and SB Ra pregnancies being 141.5 +/- 0.7, 141.7 +/- 0.7, and 149.3 +/- 0.9 days, respectively. In this study fetal endocrine changes were largely controlled in the MB pregnancy by the fetal co-twin exhibiting a shorter gestational period.

Studies on the endocrinology of parturition: relative steroidogenesis in coexisting genetically dissimilar ovine fetuses, concomitant with the temporal patterns of maternal C18 and C19 steroids and prostaglandin F2 alpha release.

The effects of corticosteroid treatment appear to represent precocious development of normal biochemical, physiologic and morphologic events in pulmonary differentiation (Chap 1 and 2) Most, if not all, of these effects are mediated through receptor, indicating that physiologic concentrations of glucocorticoid are sufficient to produce a response (Chap 3) Glucocorticoids also regulate developmental processes in a variety of other tissues of fetal and newborn animals (Ballard 1979a) These considerations support the concept that endogenous corticoids influence the timing of normal lung development and that administration of glucocorticoid mimics the action of endogenous hormone In this chapter I review the evidence that endogenous glucocorticoids have a physiologic role in lung maturation Previous discussions of this topic include reviews by Taeusch and Avery (1977), Smith (1979), and Ballard (1982a)

Role of Endogenous Corticosteroids

The role of Adrenocorticotrophin (ACTH), administered in physiological doses (12 micrograms/d), on lung maturation was investigated in the intact ovine fetus at 127-130 days of gestation. ACTH1-24 was administered in a pulsatile or continuous dose for 72 hours. Compared to untreated twins (n = 4) and saline infused fetuses (n = 4), the lungs of the pulsatile-ACTH (n = 10) and continuous-ACTH (n = 4) treated fetuses showed accelerated prepartum maturation by all indices used. Lung distensibility (V40-ml of air per g of wet lung at 40 cm H2O pressure), as determined by pressure-volume curves with air was 1.62 +/- 0.18 vs 0.72 +/- 0.23 and 0.66 +/- 0.12 while the stability (Vo-ml of air per g of wet lung at atmospheric pressure) was 0.33 +/- 0.07 vs 0.10 +/- 0.01 and 0.21 +/- 0.09 for the P-ACTH group vs the control groups (P less than 0.005). In the continuous-ACTH group vs their untreated twins the distensibility was 1.58 +/- 0.10 vs 0.56 +/- 0.11 while the stability was 0.83 +/- 0.20 vs 0.09 +/- 0.01 respectively (less than 0.005). Phosphotidylcholine concentration in lavage fluid increased from 0.05 +/- 0.02 mg/g of lung to 0.24 +/- 0.07 in the pulsed-ACTH group compared to untreated twin fetuses (P less than 0.05). Morphologically the lungs of the treated groups were well aerated with thin walled airsacs. In both treated groups, there was a doubling of the adrenal weight (P less than 0.005). Fetal plasma cortisol basal level increased from less than 5 ng/ml to 143.5 +/- 66.5 ng/ml in the continuous-ACTH group while it only rose to 36.6 +/- 7.5 ng/ml in the pulsed-ACTH group by 72 hours. Superimposed on the rise in basal fetal cortisol, there was an acute increase in cortisol temporally related to each ACTH pulse; the peaks reaching levels indistinguishable from the levels of the continuous-ACTH infusion. It is concluded that the administration of low doses of ACTH markedly accelerate prepartum maturation of the intact ovine lung over 72 hours. The mechanism by which ACTH exerts this powerful maturation effect on the fetal lung remains to be elucidated.

Accelerated prepartum maturation of the fetal sheep lung with physiological doses of andrenocorticotrophin.

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

P. G. Harding

Author Tools

Chat about Author

Papers

Accelerated prepartum maturation of the fetal sheep lung with physiological doses of andrenocorticotrophin.