Rodney A. Mead

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  • R A Mead
  • The Journal of experimental zoology
  • 1993
Embryonic diapause occurs in many species of vertebrates, but the physiological mechanisms which control this fascinating process are exceedingly different in the diverse groups which employ this reproductive strategy. In nonmammalian species and some bats, reduction in rate of embryonic development is temperature dependent, but this is not the case in most(More)
The pharmacokinetics of vitamin C after a 500-mg oral tablet dose were compared in 15 healthy young men aged 25.20 +/- 2.54 (means +/- SD) and in 15 healthy elderly men aged 69.31 +/- 2.52 y. The doses were characterized with the subjects in two states of vitamin C nutriture: a depleted state, which was achieved by 4-5 wk of compliance with a vitamin(More)
Steroidogenic cells in the corpus luteum of the ferret (Mustela putorius) during early (Days 6 and 13) to midpregnancy (Day 24) were characterized using electron microscopy, immunocytochemical localization of neurophysin, and smears of dispersed cells obtained by dissociating luteal cells with collagenase. The latter were stained for 3 beta-hydroxysteroid(More)
A cytogenetic examination of spreaded cells of diapausing and early activated blastocysts obtained from 7 female western spotted skunks was performed. Mitosis was not observed in 1626 cells obtained from 9 diapausing blastocysts; however, 12 (1.5%) figures of diploid mitosis were seen in 851 cells from 5 early activated embryos. Diameter of the cell nuclei(More)
Experiments were designed to test the hypothesis that the pineal gland mediates the effects of changing day length and thereby synchronizes implantation within the population of spotted skunks. Intact, sham-superior cervical ganglionectomized (SCGx), SCGx, and SCGx/bilateral orbitally enucleated (B1) pregnant skunks were subjected to a natural photoperiod,(More)
This study was designed to test the hypothesis that ferret corpora lutea (CL) secrete a compound that acts in conjunction with progesterone to induce blastocyst implantation and to identify the chemical nature of this compound. CL and the residual ovarian tissue, obtained predominantly on the ninth day of pseudopregnancy, were extracted with 0.05 M(More)
Three doses of FSH were tested for their ability to induce oestrus in ferrets. A dose of 0.25 mg, administered twice daily, induced oestrus and breeding in most females within 6-13 days. Addition of 5 i.u. hCG during the final stages of follicular development enhanced the percentage of females with implantation sites (85%), and 23% of the ferrets so treated(More)