Local Control of Luteal Function by the Uterus of the Guinea-pig

SUMMARY Under stereotaxic guidance, the connexions between the hypothalamus and the rest of the brain were severed surgically in mature female guinea-pigs, and reproductive function was assessed by following the vaginal cycle and by histological study of the ovaries. Animals in which the hypothalamic island incorporated the suprachiasmatic nuclei, or in which the anterior connexions to the hypothalamus were severed by a cut placed just anterior to the suprachiasmatic nuclei, developed persistent vaginal oestrus. Such an anterior cut in the hypothalamus did not influence luteal function in hysterectomized animals. When the anterior border of a hypothalamic island, or an anterior cut through the hypothalamus, was caudal to the suprachiasmatic nuclei, oestrous cycles continued although they were slightly irregular. The ovaries contained corpora lutea. Severance of the posterior connexions to the hypothalamus did not alter the oestrous cycle. The role of the suprachiasmatic area in the generation of persistent vaginal oestrus is discussed.

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Autoradiographical localization of oxytocin-binding sites in the guinea-pig ovary at different stages of the oestrous cycle

Journal of Endocrinology ◽

10.1677/joe.0.1310421 ◽

1991 ◽

Vol 131 (3) ◽

pp. 421-NP ◽

Cited By ~ 4

Author(s):

L. Zhang ◽

J. J. Dreifuss ◽

M. Dubois-Dauphin ◽

E. Tribollet

Keyword(s):

Guinea Pig ◽

Binding Sites ◽

Ovarian Function ◽

Specific Binding ◽

Corpora Lutea ◽

Luteal Function ◽

Specific Binding Sites ◽

Ovarian Stroma ◽

Theca Externa ◽

Theca Interna

ABSTRACT The discovery that oxytocin is synthesized and stored in corpora lutea of ruminants has fostered a renewed interest in the possible roles of oxytocin in ovarian function. In the present study we describe the distribution of binding sites for oxytocin in the guinea-pig ovary. Sections were reacted with a radioiodinated oxytocin antagonist (125I-labelled OTA) to yield autoradiograms on film. Specific binding sites for oxytocin were defined as those which bound 0·05 nmol 125I-labelled OTA/l and where 1 μmol non-radioactive oxytocin/1 displaced the radioactivity. 125I-Labelled OTA consistently labelled the ovarian stroma and the theca interna, but not the corpora lutea, the granulosa cells or the theca externa. The amount of 125I-labelled OTA bound to ovarian stroma and theca interna was high in animals killed during dioestrus, and low during and shortly after oestrus. These data suggest that the binding sites are regulated by steroid hormone levels and that in the guinea-pig ovary oxytocin could exert a role in follicular steroidogenesis, maturation or ovulation rather than in luteal function. Oxytocin-binding sites were also shown in the uterus but their numbers varied only slightly during the cycle. Journal of Endocrinology (1991) 131, 421–426

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ON THE SCOPE AND MECHANIÓSMS OF LOCAL CONTROL OF NEUROTRANSMITTER SECRETION FROM INDIVIDUAL VARICOSITIES OF THE SYMPATHETIC NERVES OF THE GUINEA-PIG AND MOUSE VAS DEFERENS

Receptors and Centrally Acting Drugs Pharmacokinetics and Drug Metabolism ◽

10.1016/b978-0-08-034191-0.50005-2 ◽

1986 ◽

pp. 3-12 ◽

Cited By ~ 1

Author(s):

L. STJÄRNE

Keyword(s):

Guinea Pig ◽

Local Control ◽

Vas Deferens ◽

Sympathetic Nerves ◽

Mouse Vas Deferens ◽

Neurotransmitter Secretion

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Decision letter for "The Effect of Optic Nerve Section on Form Deprivation Myopia in the Guinea Pig"

10.1002/cne.24961/v1/decision1 ◽

2020 ◽

Keyword(s):

Optic Nerve ◽

Guinea Pig ◽

Nerve Section

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Effect of Contraceptive Steroids on the Endometrium of Guinea Pig: SEM study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080766 ◽

1977 ◽

Vol 35 ◽

pp. 668-669

Author(s):

Mai M. Said ◽

Ramesh K. Nayak ◽

Randall E. McCoy

Keyword(s):

Guinea Pig ◽

Reproductive Tract ◽

Three Dimensional ◽

Female Reproductive Tract ◽

Human Female ◽

Surface Ultrastructure ◽

Transmission Electron ◽

Sem Study ◽

Uterine Mucosa ◽

Group 1

Burgos and Wislocki described changes in the mucosa of the guinea pig uterus, cervix and vagina during the estrous cycle investigated by transmission electron microscopy. More recently, Moghissi and Reame reported the effects of progestational agents on the human female reproductive tract. They found drooping and shortening of cilia in norgestrel and norethindrone- treated endometria. To the best of our knowledge, no studies concerning the effects of mestranol and norethindrone given concurrently on the three-dimensional surface features on the uterine mucosa of the guinea pig have been reported. The purpose of this study was to determine the effect of mestranol and norethindrone on surface ultrastructure of guinea pig uterus by SEM.Seventy eight animals were used in this study. They were allocated into two groups. Group 1 (20 animals) was injected intramuscularly 0.1 ml vegetable oil and served as controls.

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Ultrastructure and Drug Metabolism in the Developing Guinea Pig

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073131 ◽

1973 ◽

Vol 31 ◽

pp. 538-539

Author(s):

W. Kuenzig ◽

M. Boublik ◽

J.J. Kamm ◽

J.J. Burns

Keyword(s):

Guinea Pig ◽

Metabolic Activity ◽

Animal Species ◽

Adult Animal ◽

Smooth Endoplasmic Reticulum ◽

Fetal Life ◽

Mixed Function Oxidase ◽

Cytochrome P 450 ◽

Microsomal Mixed Function Oxidase ◽

Mixed Function Oxidase Activity

Unlike a variety of other animal species, such as the rabbit, mouse or rat, the guinea pig has a relatively long gestation period and is a more fully developed animal at birth. Kuenzig et al. reported that drug metabolic activity which increases very slowly during fetal life, increases rapidly after birth. Hepatocytes of a 3-day old neonate metabolize drugs and reduce cytochrome P-450 at a rate comparable to that observed in the adult animal. Moreover the administration of drugs like phenobarbital to pregnant guinea pigs increases the microsomal mixed function oxidase activity already in the fetus.Drug metabolic activity is, generally, localized within the smooth endoplasmic reticulum (SER) of the hepatocyte.

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Glycogen in guinea pig neutrophils: Ultrastructural study of neutrophils at the intradermal site of BCG injection

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077207 ◽

1983 ◽

Vol 41 ◽

pp. 726-727

Author(s):

Corazon D. Bucana

Keyword(s):

Bone Marrow ◽

Guinea Pig ◽

Electron Density ◽

Peritoneal Cavity ◽

Ultrastructural Study ◽

Guinea Pigs ◽

Random Distribution ◽

Glycogen Content ◽

Polymorphonuclear Neutrophils ◽

Ultrastructural Studies

In the circulating blood of man and guinea pigs, glycogen occurs primarily in polymorphonuclear neutrophils and platelets. The amount of glycogen in neutrophils increases with time after the cells leave the bone marrow, and the distribution of glycogen in neutrophils changes from an apparently random distribution to large clumps when these cells move out of the circulation to the site of inflammation in the peritoneal cavity. The objective of this study was to further investigate changes in glycogen content and distribution in neutrophils. I chose an intradermal site because it allows study of neutrophils at various stages of extravasation.Initially, osmium ferrocyanide and osmium ferricyanide were used to fix glycogen in the neutrophils for ultrastructural studies. My findings confirmed previous reports that showed that glycogen is well preserved by both these fixatives and that osmium ferricyanide protects glycogen from solubilization by uranyl acetate.I found that osmium ferrocyanide similarly protected glycogen. My studies showed, however, that the electron density of mitochondria and other cytoplasmic organelles was lower in samples fixed with osmium ferrocyanide than in samples fixed with osmium ferricyanide.

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