The temporal relationship between the pulsatile patterns of plasma luteinizing hormone (LH) and progesterone (P4) was studied in mid-luteal (ML) and early-pregnant (EP) dairy cows. Blood samples were collected (via external jugular vein cannulae) at 10-min intervals for 16 h in 5 ML cows (d 10 to 12 of the cycle) and for 10 h in 5 EP cows (d 52 to 56 of gestation). Concentrations of LH and P4 w...

Two graphs G and H with the same vertex set V are P4-isomorphic if every four vertices {a, b, c, d} ⊆ V induce a chordless path (denoted by P4) in G if and only if they induce a P4 in H. We call a graph split-perfect if it is P4-isomorphic to a split graph (i.e., a graph being partitionable into a clique and a stable set). This paper characterizes the new class of split-perfect graphs using the...

The objective of this study was to determine the temporal and spatial expression patterns of genes encoding transporters, as well as selected secreted proteins that may be regulated by progesterone (P4) and/or the presence of the conceptus in the bovine endometrium. Estrus-synchronized beef heifers were randomly assigned to either: 1) pregnant, high P4; 2) pregnant, normal P4; 3) cyclic, high P...

BACKGROUND Until recently, the corpus luteum (CL) was considered to be the main source of progesterone (P4) during pregnancy in the domestic cat (Felis catus). However, other possible sources of P4 have not been ruled out. Although feline placental homogenates were found to be capable of synthesizing P4, expression of the respective steroidogenic enzymes has not been investigated at the molecul...

P4 ATPases catalyze the translocation of phospholipids from the exoplasmic to the cytosolic leaflet of biological membranes, a process termed "lipid flipping". Accumulating evidence obtained in lower eukaryotes points to an important role for P4 ATPases in vesicular protein trafficking. The human genome encodes fourteen P4 ATPases (fifteen in mouse) of which the cellular and physiological funct...

Evidence exists for a gender difference in the vulnerability to either stroke or traumatic brain injury (TBI) in humans. For example, pre-menopausal women with the high serum levels of ovarian hormones estrogen (E2) and progesterone (P4) have a lower risk of stroke (Kannel et al., 1994; Sacco et al., 1997) and a better outcome following stroke (Thorvaldsen et al., 1995) or TBI (Groswasser et al...

Two experiments were conducted to determine how steroid milieus and pregnancy affect sexual behavior. Experiment 1 was arranged as a Latin square with five ovariectomized cows and five steroid milieus: no steroid (N); progesterone (P4); estradiol benzoate (EB); P4 + EB; and P4 followed by EB (P4:EB). Progesterone was administered via pessary (2 g of P4) for 5 d and EB was injected (1 mg i.m.) o...

The anteroventral periventricular (AVPV) nucleus of the hypothalamus integrates estradiol (E2) and progesterone (P4) feedback signals from the ovaries to stimulate gonadotropin releasing hormone (GnRH) neurons and trigger an ovulatory surge in luteinizing hormone (LH). E2 maintains the daily cyclic LH surge and P4 quickly amplifies the surge and limits it to one day. P4 amplification of the sur...

This paper discusses a project carried out at the Digital Laboratories of the Twente University of Technology. The purpose of the project was twofold: Firstly, to develop a digital hardware design and test method. Secondly, to build a hardware interpreter for an intermediate code of Pascal, the so'called P4 code. The implemented P4 machine is based on AM2901 bit slices. During the project a P4 ...