Recent Progress in Hormone Research (eBook)

Proceedings of the 1972 Laurentian Hormone Conference

Roy O. Greep (Herausgeber)

eBook Download: EPUB

2013 | 1. Auflage
622 Seiten
Elsevier Science (Verlag)
978-1-4832-1949-3 (ISBN)

Infos

Recent Progress in Hormone Research, Volume 29 covers the proceedings of the 1972 Laurentian Hormone Conference held in Mont Tremblant, Province of Quebec, Canada, on August 27-September 1, 1972. The book discusses the studies on sex differentiation in mammals; male pseudohermaphroditism in the laboratory Norway rat; and androgen metabolism and mechanism of action in male pseudohermaphroditism. The text also describes the mechanism of initiation of parturition in the ewe; the neurovascular regulation of the anterior hypophysis; and microtubules and beta cell secretion. The role of microtubules and microfilaments in thyroid secretion; the functional and morphological alterations produced in target cells by anti-inflammatory steroids; and protein kinases are also considered. The book further tackles the role of phospholipids in hormone activation of adenylate cyclise; the chemistry of growth hormone and the lactogenic hormones; and hormonal regulation of gene expression in mammary cells. The text then encompasses the endocrine and metabolic effects of experimental obesity in human; the studies on luteinizing hormone and its subunits; and chemical studies of luteinizing hormone from human and ovine pituitaries. The studies on the structure and function of interstitial cell-stimulating hormone are also looked into.

Textauszug

Part I. Male Pseudohermaphroditism in the Laboratory Norway Rat1

ALLAN J. STANLEY, LAURENCE G. GUMBRECK and JOHN E. ALLISON,     Departments of Physiology and Biophysics and of Anatomical Sciences, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma

RONALD B. EASLEY,     Duke University Hospital, Durham, North Carolina

Publisher Summary

This chapter presents an analysis of male pseudohermaphroditism in the rat with regard to anatomic, embryologic, genetic, and physiological considerations. The anomaly is transmitted genetically by female carriers to one-half of their male offspring. In addition, one-half of the female offspring of an affected sibship become carriers. Affected males exhibit, in general, a female phenotype characterized by the presence of a blindly ending vaginal recess and mammary line but lack both Müllerian and Wolffian duct systems. Embryologic studies show normal development of Wolffian and Müllerian duct systems up to day 17 in utero, at which time disintegration of these structures takes place. Hence, a male inductor system seems not to be involved, but rather a maintenance factor without which disintegration of the ductal system results. The lack of androgen sensitivity demonstrated in these animals appears to be a reasonable explanation in light of present information. Spermatogenesis does not progress beyond the primary spermatocyte stage in the testes of the pseudohermaphrodite. The interstitial cells show marked proliferation, an indication of gonadotropin stimulation.

I Introduction

In 1941, D’Amour and Funk in a paper entitled “Spontaneous Inter-sexuality in the Rat” described anatomically a condition closely resembling one that has appeared in our rat colony and has been successfully isolated and propagated as a substrain of our King2 × Holtzman hybrids. Eight individuals appeared in their colony over a period of two years, and, although attempts were made to find the parents of these animals, they could not be identified and the stock was subsequently lost. The only additional case of this type of intersex in the rat was reported by Matthews (1947) in a single specimen of the wild Norway rat. This animal possessed nipples, a perforate vagina, two flattened sterile testes and other rudimentary accessories.

The following trivial names and abbreviations have been used in the text and discussion: adrenosterone = androst-4-che-3,11,17-trione; androstenedione = androst-4-ene-3,17-dione; androsterone = 3α-hydroxy-5α-androstan-17-one; dehydroepiandrosterone = 3β-hydroxy-5-androsten-17β-01; deoxycorticosterone = 21-hydroxypregn-4-one-3,20-dione; estrone = 3-hydroxyestra-1,3,5(10)-trien-17-one; 17β-estradiol = estra-1, 3,5(10)-triene-3,17β-diol; estriol = estra-1,3,5(10)-triene-3,16α,17β-triol; etiocholanolone = 3α-hydroxy-5β-androstan-17-one; progesterone = pregn-4-ene-3,20-dione; 17-hydroxyprogesterone = 17-hydroxypregn-4-ene-3,20-dione; pregnenolone = 3β-hydroxy-5-pregnen-20-one; 17-hydroxypregnenolone = 3β,17-dihydroxy-5-pregnen-20-one; testosterone = 17β-hydroxyandrost-4-en-3-one; PMS = pregnant mare serum; HCG = human chorionic gonadotropin; FSH = follicle-stimulating hormone; LH, luteinizing hormone.

II Materials and Methods

a Experimental Animals.

Male pseudohermaphrodite rats employed in the present study were derived from a strain of King × Holtzman hybrids out of which this anomaly arose. Littermate male and female rats were used in all experimental studies as controls.

b Embryological Studies.

Embryos were removed at different stages of development from females that had produced one or more litters containing pseudohermaphrodites. The day of first appearance of spermatozoa in vaginal smears was taken as day 1 of gestation.

c Testosterone Administration.

Adult pseudohermaphrodite rats were divided into 4 random groups; one group served as controls and the other 3 groups were injected with 4, 5, and 6 mg of testosterone propionate in oil daily for 40 days, at which time all animals were autopsied and body weights, along with weights of the endocrine organs and kidneys, were recorded.

d Steroid Determinations.

Urine for steroid determinations was collected by placing experimental and control rats in metabolic cages. Urine was collected at 12-hour intervals; the volume was measured and pooled into 24-hour collections.

e Urinary 17-Deoxycorticosteroids.

The determination of total urinary 17-deoxycorticosteroids included the 21-hydroxypregnan-20-ones and pregnane-20:21-diols. The chemistry was carried out according to the method of Exley and co-workers (1961). The principle involved in this determination is based on the oxidation of the C20:21 constituent to a C20 aldehyde. The Angeli-Ramini colorimetric reaction is then used for the detection of the aldehyde. Nine separate determinations were done for each group of animals.

f Urinary 17-Ketosteroids.

The method of determination of total urinary 17-ketosteroids was that of Drekter et al. (1952). This method relies on the fact that steroids containing the group —COCH2— will give a purple color when treated with m-dinitrobenzene in the presence of alkali (Zimmermann reaction). Ten separate determinations were done for each group of animals.

g Gonadotropin Assays.

Animals used for the bioassay of LH were females of the Holtzman strain. At 21 days of age they were prepared for bioassay with pregnant mare serum (PMS) (50 IU) followed 60 hours later by human chorionic gonadotropin (HCG) (25 IU). They were used for bioassay from 6 to 8 days following administration of HCG. Animals employed for the bioassay for follicle-stimulating hormone (FSH) were female King × Holtzman rats. At 22 days of age they were hypophysectomized by the parapharyngeal approach. The animals were used immediately after hypophysectomy for bioassay of FSH.

h Luteinizing Hormone (LH) Assay.

LH was assayed according to the method of ascorbic acid depletion of Parlow (1961). Each assay included 2 doses of NIH-LH-S11 reference standard (0.4 μg and 1.6 μg) in addition to two doses of the unknown pituitary extract (normal male pituitary at doses of 50 μg and 200 μg and pseudohermaphrodite pituitary at doses of 25 μg and 100 μg). A control group received only 0.9% saline. Ten assay animals were used for each dosage level. Estimates of potency of the pituitary extract were expressed in terms of the reference standard. Values for the slope and standard deviation of the dose-response curves were calculated according to the method of Finney (1964). Ascorbic acid content of the ovaries from bioassay animals was determined by the method of Mindlin and Butler (1938) as modified by Parlow (1961). The principle involves decoloration of the dye 2,6-dichlorophenolindophenol which is proportional to the concentration of ascorbic acid over the range employed.

i FSH Assay.

The method used for the bioassay of FSH was that of Payne et al. (1959). In this particular method the end point is taken as the increase in ovarian weight over that of control rats. Diethylstilbestrol is used as a synergizing agent; it is injected separately but at the same time with the pituitary powder and reference standard. A synergizing agent is used to sensitize the ovary so that it may respond to a smaller dose of the pituitary powder. The pituitary powder and reference standard (normal male and pseudohermaphrodite pituitary powder at doses of 0.8 mg and 1.6 mg and NIH-FSH-S3 at the same doses) were divided into 4 doses and given over a period of 4 days. The ovaries of the hypophysectomized assay animals were removed 48 hours after the last injection and weighed. Ten hypophysectomized animals were used in the assay for each dosage level. The potency of the pituitary preparation is given as a percentage of purified NIH-FSH-S3 reference standard. The relative potency was calculated according to the method of Finney (1964).

j Parabiosis Experiments.

At the time of surgical union, both experimental and assay rats were 30–33 days of age and weighed 80–90 gm. The animals remained in surgical union for 15 days, then the ovaries were removed from the female parabiont and weighed. Pseudohermaphrodite and male rats were castrated at the time of parabiotic union. (See Table IV for details.)

TABLE IV

Ovarian Weight Response of Female Rats in Parabiosis for 15 Days with Unoperated and with Castrate Male Pseudohermaphrodite Siblingsa

aAt the time of surgical union, both experimental and female parabionts were 30–33 days of age and weighed 80–90 gm. Values are expressed...

Produkt-Details

• Erscheint lt. Verlag: 22.10.2013
• Sprache: englisch
• Themenwelt: Informatik ► Weitere Themen ► Bioinformatik
• Themenwelt: Medizinische Fachgebiete ► Innere Medizin ► Endokrinologie
• Themenwelt: Studium ► 1. Studienabschnitt (Vorklinik) ► Biochemie / Molekularbiologie
• Themenwelt: Naturwissenschaften ► Biologie ► Genetik / Molekularbiologie
• ISBN-10: 1-4832-1949-6 / 1483219496
• ISBN-13: 978-1-4832-1949-3 / 9781483219493