Antioxidant enzymatic activity in embryos and placenta of rats chronically exposed to hypoxia and hyperoxia.

Embryos exhibit lower enzymatic antioxidant activity (EAOA) than adults, in accordance with the low in utero oxygen concentration. We asked whether external oxygen stress can modulate embryonic EAOA and what the placenta role is a mediator between embryos and external milieu. Pregnant rats were exposed to hyperoxia (90% O2) or hypoxia (10% O2) during 8 days in the second or third trimester.

Heart and lung adaptations to pregnancy and lactation in a crocidurine shrew.

Heart and lung mass, rate of oxygen consumption (VO2), respiration rate (fR), tidal volume (VT), and heart rate (fH), were measured at rest and thermoneutrality in the shrew Crocidura russula monacha [(This shrew is claimed to be Crocidura suaveolens (Catzeflis, F., T. Maddalena, S.

The effect of hexapeptides on attachment and outgrowth of mouse blastocysts cultured in vitro: evidence for the involvement of the cell recognition tripeptide Arg-Gly-Asp.

Differentiation of the nonadherent trophectoderm cells of the mammalian embryo into attachment-competent trophoblast cells appears to be a prerequisite to invasion of the uterine stroma. To investigate the molecular basis of trophoblast differentiation free of maternal environmental constraints, we used a model system in which attachment and outgrowth of trophoblast cells occurs in vitro. Recently, it was found that either fibronectin or laminin, both of which are extracellular matrix glycoproteins of the uterine stroma, will support trophoblast outgrowth in vitro.

Methimazole pharmacology in the rat: studies using a newly developed radioimmunoassay for methimazole.

Methimazole [1-methyl-2-mercaptoimidazole (MMI)] was given to normal male rats in their drinking water in concentrations ranging from 0.0001-0.05% for either 1 week or 1 month.

Mouse pituitary tumor line secreting only the alpha-subunit of the glycoprotein hormones: development from a thyrotropic tumor.

This report describes the conversion of a murine pituitary thyrotropic tumor (MGH 101) to a pure alpha-subunit-secreting tumor (MGH 101A) during a 6-yr period of serial transplantation. MGH 101 was a thyrotropic tumor originating from a hypothyroid mouse pituitary, growing only in hypothyroid hosts, and secreting large quantities of intact TSH and free alpha-subunit. Between the fourth and ninth transplantation generations, tumor TSH secretion declined progressively by at least 500-fold, to undetectable levels.