Richard J Krieg

Learn More
The effects of systemic recombinant human interleukin-2 (rIL-2) infusion on cerebrovascular permeability to an endogenous circulating macromolecule, immunoglobulin G (IgG), were assessed in rats after single and multiple rIL-2 infusions. Ultrastructural detail of the cerebral vasculature and the related brain parenchyma was also examined for rIL-2-related(More)
A single gene defect of the circadian clock (tau mutation) has recently been described that results in a shortening of the circadian activity cycle of the Syrian hamster. In the homozygous animal, free running activity is shortened by 4 h, resulting in a circadian period of approximately 20 h. Here, we examine the effect of the tau mutation on noncircadian(More)
The rapidly reversible increase in cortical or midbrain tryptophan hydroxylase activity observed ex vivo after exposure of rats to 1-h sound stress was blocked by hypophysectomy, but not sham hypophysectomy, and restored by dexamethasone administration to the hypophysectomized animals (500 micrograms/day i.p. for 3 days). The response to sound stress was(More)
Reproductive aging in female rats is associated with attenuated preovulatory LH surges. In this study, detailed analyses of the episodic characteristics of the proestrous LH surge were conducted in young and middle-aged regularly cyclic rats. On proestrus, blood samples were withdrawn at 3-min intervals for 6 h and analyzed for LH concentrations by RIA in(More)
We have found previously that rat diaphyseal bone in vivo, as well as rat embryo calvaria cells in culture, show a sex-specific response to gonadal steroids in stimulation of creatine kinase (CK)-specific activity, and the rate of [3H]thymidine incorporation into DNA; male-derived cells responded only to testosterone or to dihydrotestosterone (DHT), whereas(More)
The present study was designed to investigate the effect of intracerebroventricular infusion of norepinephrine (NE) on the secretion of luteinizing hormone-releasing hormone (LH-RH) into the hypophysial portal blood of steroid-primed ovariectomized rats. Saline infusion into the third ventricle caused no significant change in LH-RH levels. NE infusion (20(More)
Gbomerubosclerosis and tububointerstitial injury are characteristic features seen in the subtotal (5/6) nephrectomy remnant kidney model in the rat. Oxidative stress from renal mass reduction contributes to the gbomerubar and tubular injury. Previous studies have clearly demonstrated the prevention or inhibition of such injury by an antioxidant such as(More)
Several studies have shown that a certain subpopulation of middle-aged rats have an attenuated preovulatory LH surge, and that this is an early indicator of a general decline in reproductive cyclicity. The pituitary glands of middle-aged animals with attenuated LH surges have been shown to be significantly less responsive to GnRH than those from young (Y)(More)
Prior to the cessation of regular cyclicity, middle-aged rats display pre-ovulatory luteinizing hormone (LH) surges of reduced magnitude. The present study was designed to identify whether middle-aged female rats with attenuated proestrous LH surges have alterations in pituitary responsiveness to gonadotropin-releasing hormone (GnRH). Young (4 months old)(More)
To investigate possible mechanisms whereby the augmentation of hypothalamic proopiomelanocortin (POMC) messenger ribonucleic acid (mRNA) levels occurs with pubertal development, we employed the techniques of testosterone administration and in situ hybridization histochemistry in sexually immature male rats. Six animals from each of the following groups were(More)